Fingerprint Identification Study for Exam - PDF

**INTRODUCTION** Personal Identification has emerged as a significant element in efforts to control crime while maintaining a high quality of justice. The value of physical evidence and its analysis has been demonstrated in many ways on many occasions, and law enforcement officials have become incr...

**INTRODUCTION** Personal Identification has emerged as a significant element in efforts to control crime while maintaining a high quality of justice. The value of physical evidence and its analysis has been demonstrated in many ways on many occasions, and law enforcement officials have become increasingly dependent on laboratory results for evidence not obtainable by other avenue or means of investigation. As science and technology continue to advance, the capabilities and importance of personal identification will also continue to grow. At present, many individual cities, municipalities, and provinces have fingerprint laboratories serving them. Great forward strides made in professional law enforcement during the past 100 years must be attributed to a combination of many important developments. These include the adoption of scientific methods, the growth of modern transportation and communication facilities, the use of improved and new types of equipment and the dedication of trained career police officers. No factor can be singled out as being individually responsible for the progress which has been achieved. If an attempt were made, however, to list them in the order of their dramatic and far reaching impact, a prominent place would have to be given to the science of fingerprint identification. In the field of personal identification, the fingerprint has come to be closely associated in the mind of the lay person with the problems of locating and identifying offenders. Thousands of law breakers each year are made to face the consequences of their crimes because of minute, almost indiscernible, prints carelessly left behind. Fleeing felons are inescapably tied to their lawless past by a small cardboard square bearing the inked impression of their fingertips. In this way, well over a thousand fugitives are identified each month by law enforcement agencies. In addition to its effectiveness in criminal identification, the fingerprint has become increasingly helpful in its humanitarian uses, it can reunite joyful families with loved ones who have been missing; it provides a name and past for the unfortunate person tormented by amnesia, and in time of tragedy it resolves anguished uncertainty by establishing the identity of the disaster victim. **ETYMOLOGY OF DACTYLOSCOPY** \- It was derived from the Greek Words **DACTYLOS** which means a *finger* and **SKOPIEN** which means *to examine*. **What are the other aspects of personal identification?** 1. Identification of unknown human remains through dental records and assisting at the scene of a mass disaster 2. Age estimations of both living and deceased persons including neo-natal remains 3. Analysis of bite marks found on victims of attack 4. Identification of bitemarks in other substances such as wood, leather and foodstuffs **6. Cartography** (Portrait Parle) = cartographic sketches \- Identification of a person through drawing or sketching the physical features of the suspect. Otherwise known as "spoken picture" \"camera eyes,\" **7. Photography** = identification through pictures or photographs  8. **DNA FINGERFRINTING/ANALYSIS/PROFILING-** using the DNA pattern of a person(Identical twins have identical DNA pattern) DNA fingerprinting uses a specific type of DNA sequence, known as a [**microsatellite**](http://www.wisegeek.com/what-is-a-microsatellite.htm), to make identification much easier. Microsatellites are short pieces of DNA which repeat many times in a given person\'s DNA **Other Methods of Personal Identification** **HISTORY BACKGROUND** **JUDEA** **PAUL THE APOSTLE** **-**use his own fingerprints to sign his letter which reads as**\ "I, Paul, greet you with my own hand" (11 Thessalonians 3:17).** **INDIA** Based on records, fingerprint were observed by the early people in the smooth face of a Cliff in **Nova Scotia** Outline of a hand is covered by the lines representing ridges and furrows. **CHINA** **TANG DYNASTY** = the era where fingerprints are used in connection with the preparation of legal documents. The early practices of fingerprints are credited to the **Chinese Monarchs** who were successful in applying this method in their daily business and legal documents by means of their thumbprints as a sign manual. **Code of Domestic Relations**= a Chinese law book of **Yung Huwi** states that " to divorce a wife, the husband must write a **Bill of Divorcement** and state the reasons/grounds that are due for action, and then impressed his palm print thereon. **Story of the River bank=** in the **Criminal Procedure of China** and in the 16th century A custom prevailed in connection with the sale of children where Sole and Palm impressions were stamped on **DEEDS OF SALE** to prevent impersonation **EARLY PUBLICATION AND PIONEERS IN THE STUDY AND USE OF FINGERPRINTS** **NEHEMIAH GREW** The first person who used the scientific study on fingerprints. He described the ridges and pores of the hands and foot. **MARCELO MALPIGHI** an Italian Anatomist and **the grandfather of dactyloscopy** **-** He made a study regarding the different layers of the skin. **Epidermis(outer layer)** **Dermis(inner layer/true skin)** **Dr. Edmund Locard** -the father of poroscopy Commented on his writings on elevated ridges on the finger tips and alleged to diverse figure on palmar surfaces. He perceived the ridges to be drawn into Loops and Spirals at the end of the fingers. **(Galton\'s Details)** Edmond Locard wrote that if 12 points (Galton\'s Details) were the same between two fingerprints, it would suffice as a positive identification.  Locard\'s 12 points seems to have been based on an unscientific \"improvement\" over the eleven anthropometric measurements (arm length, height, etc.) used to \"identify\" criminals before the adoption of fingerprints.    **JCA MAYER** He stated that although the arrangement of the skin ridges is never duplicated into two (2) person, nevertheless, the similarities are closer among some individuals. Fingerprints of two (2) person are never alike. **(Principle of Individuality)** **JOHANNES EVANGELIST PURKINJIE** **Father of dactyloscopy** He involves vague differentiation of fingerprints or use them for identification. He distinguished and named 9 fingerprint patterns. **HERMAN WELCKER** He took the prints of his own palm. After 41 years, he printed the same palm to prove that the prints do not change **(Principle of Permanency)** **William James Herchel** **Dr. Henry Faulds** He ***points out that the chance prints left at the scene of crime would provide for positive identification of offenders when apprehended***. He introduced the used on thin film ink as a transfer medium in taking fingerprint impression. Additionally, he is noted as being the first person to use a latent fingerprint to eliminate someone as a suspect **SAMUEL CLEMENS ( Mark Twain)** informally introduced Dactyloscopy in the USA through his book **" Life in the Mississipi" and Pudd'n an Wilson",** a novel based on the dramatic fingerprint identification demonstrated during a court trial where his story pointed out the **Infallibility of Finerprint Identification.** **Sir Francis Galton** (1822-1911) He was credited as the **first scientist of friction skin identification** as well as his role in promoting its use. He was able to discover the three families of fingerprint patterns by dividing the first joint of the ten fingers into ***three major groups namely; ARCH, LOOP, and WHORL***. **-first scientist of friction skin identification** **PRINCIPLE OF INFALLIBILITY.** **FOUR (4) PILARS IN THE STUDY OF FINGERPRINT** **Sir Edward Richard Henry** (1859-1931) -- he was considered as the **Father of Fingerprint Science** because of his persistence in devising a workable system of classification and made it applicable to police work **Haque & Bose** On 12 June 1897,  the Council of the Governor General of India approved a committee report that fingerprints should be used for classification of criminal records.  Later that year, the **Calcutta (now Kolkata) Anthropometric Bureau** became the world\'s first Fingerprint Bureau.  Working in the Calcutta Anthropometric Bureau (before it became the Fingerprint Bureau) were **Azizul Haque and Hem Chandra Bose**.  Haque and Bose are the two Indian fingerprint experts credited with primary development of the Henry System of fingerprint classification (named for their supervisor, Edward Richard Henry).  **Juan Vucetich** Vucetich claimed that he is the first official in criminal identification by means of fingerprint left at the scene of crime. It also mark the first installation of fingerprint files a an official means of criminal identification He is consider as the father of fingerprint science in the most Spanish speaking countries **Icnofalangometric System** \- the original name of the system developed by Vucetich in 1891. Dactiloscopy - the new name of the system developed by Vucetich. **Dactiloscopy or Dactiloscopia or Dactiloscopico** The fingerprint classification system developed by Juan Vucetich and used in most areas of South America. Originally named the Icnofalangometric System and developed in 1891. **Alphonse Bertillon** (1870) -- he originated the measuring process or bodily measurements (Anthropometric system of identification) He was credited as the **Father of Criminal Identification** **Dr. Henry P. De Forest** **=** He utilized the first Municipal Civil use of Fingerprints for **"Non-Criminal Registration"** on December 1902 in the City of New York. **Gilbert Thompson** Employed by the U.S. Geological Survey in New Mexico, uses his own fingerprints on a document to guard against forgery. This event is the first known use of fingerprints for identification in America. **Ferrier, John Kenneth** He is considered to be the first fingerprint instructor in the United States. Although fingerprints had been used sporadically in the United States prior to Ferrier\'s arrival, Ferrier is credited with being the driving force behind the use of fingerprints in the U.S. **Inspector Harry H. Caldwell** Oakland, California Police Department\'s Bureau of Identification wrote numerous letters to \"Criminal Identification Operators\" in August 1915, requesting them to meet in Oakland for the purpose of forming an organization to further the aims of the identification profession. In October 1915, a group of **twenty-two identification personnel** met and initiated the \"International Association for Criminal Identification\" In 1918, the organization was renamed the **[International Association for Identification](http://www.theiai.org/) (IAI)** due to the volume of non-criminal identification work performed by members.  **Sir Francis Galton\'s** right index finger appears in the IAI logo.  The IAI\'s official publication is the Journal of Forensic Identification.   **Chatterjee, Sri Salil Kumar(1903 or 1904-Sept. 12, 1988)** Salil K. Chatterjee, of India, is recognized for developing edgeoscopy in 1962. He is also recognized as developing the only practical soleprint classification system. **Cummins, Prof. Harold (1893-1976)** Doctor Cummins is universally acknowledged as the Father of Dermatoglyphics. Harold studied all aspects of fingerprint analysis, from anthropology to genetics, from embryology to the study of malformed hands with from two to seven fingers. **Evans, Captain Michael P. (?-Oct. 7, 1931)** Implemented the Bertillon system in 1888 at the Chicago Police Department and implemented the fingerprint system in 1905 while he was the Chief of the Identity Bureau. Testified in \"People vs. Jennings\". **Holland, Mary (Feb. 25, 1868-Mar 27, 1915)** Mary and Phil Holland operated the Holland Detective Agency in the early 1900\'s. In 1904, they met Ferrier at the World\'s Fair in St. Louis. Ferrier instructed Mary Holland and eight others on fingerprints and how to use the Henry System. In 1907, Mary Holland was hired by the US Navy as a fingerprint instructor. She is considered to be the second American fingerprint instructor in the United States (second to Parke) but the first woman fingerprint instructor. Her teachings promoted the Henry System throughout the United States. Mary Holland is also credited as one of the fingerprint experts (along with Edward Foster, William M. Evans and Michael P. Evans) to testify in the trial \"People vs. Jennings\".  **UNSUCCESSFUL ATTEMPT TO TRY THE INFALLIBILITY OF FINGERPRINT SCIENCE** **(Known as Roscoe Pitts)**A career criminal noted for altering his fingerprints in 1941. He had a doctor remove the skin from his first joints and replace it with skin from his chest. **Perez, Gerald** On Feb 07, 2008 Gerald Perez was arrested on drug charges using the name Edgardo Tirado. While officials were taking his fingerprints they realized he altered his fingerprints in an attempt to conceal his identity but Perez claimed he had been in a fight when his fingers were cut. His true identity was revealed when someone recognized him as Gerald Perez, which was later confirmed. Perez had his fingers cut lengthwise and then stitched back together. Some believe this surgery took place in the Dominican Republic in order to conceal his criminal record and avoid possible deportation. **Fingerprint Use in the Philippines** **2012** The world\'s largest annual meeting of fingerprint experts is hosted by the IAI - this year it will be during [22-28 July in Phoenix](http://www.theiai.org/conference/2012/), Arizona, USA. INTERPOL\'s Automated Fingerprint Identification System repository exceeds 150,000 sets fingerprints for important international criminal records from 190 member countries.  Over 170 countries have 24 x 7 interface ability with [INTERPOL expert fingerprint services](http://www.interpol.int/INTERPOL-expertise/Forensics) **2013 - America\'s Largest Database** The largest AFIS repository  in America is operated by the Department of **Homeland Security\'s US Visit Program**, containing over **120 million persons\' fingerprints**, many in the form of two-finger records.  The **two-finger records** are non-compliant with FBI and Interpol standards, but sufficient for positive identification and valuable for forensics because **index fingers and thumbs** are the most commonly identified crime scene fingerprints.  The US Visit Program has been migrating from two flat (not rolled) fingerprints to ten flat fingerprints since 2007. largest criminal fingerprint AFIS repository The largest criminal fingerprint AFIS repository in America is the FBI\'s Integrated AFIS (IAFIS) in Clarksburg, WV.  IAFIS has more than **60 million individual computerized fingerprint records** (both criminal and civil applicant records).  **2013 - World\'s Largest Database** As of March 2013, the [Unique Identification Authority of India](http://uidai.gov.in/) operates the world\'s largest fingerprint (multi-modal biometric) system, with over 200 million fingerprint, face and iris biometric records.  UIAI  plans to collect as many as 600 million multi-modal record by the end of 2014.  India\'s Unique Identification project is also known as **Aadhaar**, a word meaning \"the foundation\" in several Indian languages.  Aadhaar is a voluntary program, with the ambitious goal of eventually providing reliable national ID documents for most of India\'s 1.2 billion residents **IMPORTANT DEFINITION OF TERMS** **Cheiloscopy** The study of lip prints. **Dry-Labbing** **Fulcrum Area** The area between the thumb and index finger on the palm. **Dorsal** The backside of the hand, the nonpalmar side. **Galton Details** Term referring to friction ridge characteristics (also known as minutiae) International Association for Identification (**IAI)** **FINGERPRINT AS AN IMPRESSION** = by means of the reproduction on the smooth surface the patterns and designs by friction ridges found at the inside of the end joints of the fingers and thumbs through a transfer medium of ink or any colored substances capable of producing visibility. **Palm print impressing** -- is to impress palms unto the palm print impression column. Impress it fully with extended palms. **General Technique or Ordinary Impressing --**  Position of Impresser/Operator -- the impressing plate is on the left side of the table while the glass plate or cardholder is on its right side. Positions of Persons -- The Impressing attendant or operator is on the left side while subject is on the right side of the operator and about 20 cm off/away from the impressing table Density of Ink -- the amount of ink needed for impression per person is the volume of a match head. **BRANCHES OF DACTYLOSCOPY** **Pelmatoscopy** The science which studies the friction ridges of the soles. Of the different aspects of personal identification, it was proven beyond reasonable doubt and the proper authorities concerned that fingerprints is **3 BASIC DOGMATIC PRINCIPLES\ OF THE STUDY OF FINGERPRINTS** 1. **Principle of Individuality (variation)** = there are no two fingers that are exactly alike unless taken from the same finger-uniqueness. That the complex ridge details in a single fingerprint or even part one is not duplicated in any other finger. **Fingerprint Identification (AKA Friction Ridge Identification or Friction Skin Identification)** The applied science of identification by friction skin based on the Theory of Differential Growth and the Theory of Permanence. Skin is one of the largest organs of the body. It is recognized as an organ because it consists of several types of tissues that function together. In addition, it includes millions of sensory receptors and an extensive vascular network. The skin is a protective, pliable covering of the body, one that is continuously replaced.  [**The Integumentary System**](http://ridgesandfurrows.homestead.com/Integument.html) includes the skin and the epidermal derivatives of hair, nails and glands. **PAPILLARY STRUCTURE/HUMAN SKIN** **Sub-divisions of Epidermis** Stratum Corneum , or Horny Layer Stratum Lucidum, or Hyalin Layer Stratum Granulosum, or Granular Layer Stratum Spinosum, or Spinous Layer Stratum Basale, or Generating Layer **Stratum corneum **- consists of 25-30 layers of stratified (layered) squamous (flattened) dead keratinocytes (skin cells) that are constantly shed. **Stratum lucidum **- is present only in thick skin (lips, soles of feet, and palms of hands). Little or no cell detail is visible. **Stratum granulosum **- 3-4 layers of cell thick consisting of flattened keratinocytes.  At this level the cells are dying. **Stratum spinosum **- several layers thick, consisting mostly of keratinocytes.  Together with the stratum basale it is sometimes referred to as the Malpighian layer (living layer). **Stratum basale** - a single layer of cells in contact with the basement membrane.  These cells are mitotically active - they are alive and reproducing - the reason why it is often referred to as the generating layer.  Four types of cells are present in this layer: **Basement Membrane** A thin, delicate layer of connective tissue underlying the epithelium of many organs. Also called basement lamina. A membrane separating the dermis from the epidermis. The basement membrane consists of an upper layer, (lamina lucida) and a lower layer (lamina densa). **Friction Ridge Path** The paths or deviations of a friction ridge (endings and bifurcations). referred to as 2nd level details.  **Friction Ridge Shapes -** The shapes (width and contour) of the ridges. Also referred to as 3rd level details.  **Friction Ridge Unit -** A theoretical length of measurement. Cell progression The entire progression of keratinocytes in the basal layer until it reached to the horny layer, the cells (keratinocytes) are always bound by **desmosomes**. After keratinizations occur, cells will slough off like scales in the atmosphere. This process is called **desquamation**. **FRICTION SKIN FORMATION** **Stages :** Swelling of the volar pads. The volar pads start to regress. Primary ridges form.Sweat glands develop. Secondary ridges develop. Anastomoses form. Dermal papillae are created. Mechanical Fusion Theory: As existing ridges separate, a demand for new ridges is created because the surface has a tendency to be continually ridged **TWO TYPES OF RIDGE DESTRUCTION** 1\. Permanent Destruction -- will not re-appear anymore 2\. Temporary destruction- it will re-appear **So, do identical twins have identical fingerprints?** The basic answer is **NO.** Identical \-- or monozygotic \-- twins form when a single fertilized egg splits in two after conception. Because they form from a single zygote, the two individuals will have the same genetic makeup. Their DNA is virtually indistinguishable. However, fingerprints are not an entirely genetic characteristic. Scientists love to use this topic as an example of the old \"nature vs. nurture\" debate. Fingerprinting, along with other physical characteristics, is an example of a phenotype \-- meaning that it is determined by the interaction of an indivdual\'s genes and the developmental environment in the uterus. The ultimate shape of fingerprints are believed to be influenced by environmental factors during pregnancy, like nutrition, blood pressure, position in the womb and the growth rate of the fingers at the end of the first trimester. Thus, you will find similar patterns of whorls and ridges in the fingerprints of identical twins. But there will also be differences \-- just as there are differences between the fingers on any individual\'s hands. **Phalange (Phalanx)** Any bone in the fingers is referred to as a phalanx (or phalange). The fingers each having 3; the distal phalanx, the medial or middle phalanx, and the proximal phalanx. The thumb has two; the distal phalanx and the proximal phalanx. Phalanx is more frequently used for the singular form of the word and phalanges is more frequently used for the plural form of the word, but phalange or phalanxes can be substituted.  The proximal phalange bone incorporates a finger segment as well as part of the interdigital area. **PATTERN AREA** is the only part of the finger impression with which we are concerned in regard to interpretation and classification. That part of a loop or whorl in which appear the cores,deltas, and ridges with which we are concerned in classifying. The pattern areas of loops and whorls are enclosed by type lines. **ELEMENTS OF A PATTERN AREA\ **1. There must be a CORE/s appearing on the pattern area\ 2. There must be DELTA/s appearing on the pattern area\ 3. Other ridges wherein concerned in the interpretation and classification of fingerprints. **TYPE LINES** may be defined as the two innermost ridges which start parallel, diverge and surround or tend to surround the pattern area. Type lines are not always two continuous ridges **BIFURCATION** is the forking or dividing of one line into two or more branches. **DIVERGENCE** is the spreading apart of two lines which have been running parallel or nearly parallel. **FOCAL POINT --** Within the pattern areas of loops and whorls are enclosed the focal points which are used to classify them. These points are called delta and core. **DELTA** (outer terminus) is that point on a ridge at or in front of and nearest the center of the divergence of the type lines. It may be: a\. A bifurcation b\. An abrupt ending ridge c\. A dot d\. A short ridge e\. A meeting of two ridges f\. A point on the first recurving ridge located nearest to the center and in front of the divergence of the type lines. **CORE (Inner terminus)**, as the name implies, is the approximate center of the finger impression. It will be necessary to concern ourselves with the core of the loop type only. **Focal Points** 1\. **In Fingerprint Identification**. Focal points may include a delta, core, creases, scars, or the flow of friction ridge detail (as with a recurve). Focal points may be used for searching but not necessarily be used in arriving at a conclusion during the ACE-V process. The search parameters are increased for prints with limited or no focal points. 2\. **In the Henry Classification**, focal points refer specifically to the core and deltas areas. 3\. The term focal point is occasionally used to refer to a target group. **RIDGE CHARACTERISTICS/ "MINUTIAE"** **17. Envelope** -- a ridge that surrounds the rod bars. **18. Rod** -- a ridge inside a recurving ridge. **Dysplasia** Ridge units that did not form complete friction ridges due to a genetic cause. **Bracelet Creases** The creases located at the base of the palm. Usually where the friction skin ends. **Flexion Crease** Creases that are formed during friction ridge formation, completely lacking of any ridge detail. Flexion creases are unique and permanent. . **Proximal Inter-Phalangeal Flexion Crease** The crease which separates the fingers from the palm. **Metacarpo-phalangeal Crease** **Medial Interphalangeal Flexion Crease** The middle crease on a finger. **BERTILLON SYSTEM** **Bertillonage** Bertillon\'s method of anthropometry. = by body measurement = otherwise known as the anthropometric system of identification 1870. **BASIS:** 1\. Human skeleton does not change after 20 yrs. 2\. It is impossible for two (2) human beings to have bones alike. 3\. Measurement easily taken with the aid of simple instrument. **CHARACTERISITICS OF INDIVIDUAL** A. Description data, such as color of the hair, eyes, complexion, shape of nose and ear. B. Body marks such as moles, scars and tattoo. C. Body measurement. = standing height = arm reach = sitting height = breadth of head = length of left foot = cheek breadth = length of right ear = length of middle finger = length of little finger = length of left forearm = length of left forearm and hand The Bertillon System was generally accepted for thirty years. But it never recovered from the events of 1903, when a man named Will West was sentenced to the U.S. Penitentiary at Leavenworth, Kansas. It was discovered that there was already a prisoner at the penitentiary at the time, whose Bertillon measurements were nearly the same, and his name was William West. Upon investigation, there were indeed two men who looked exactly alike. Their names were Will and William West respectively. Their Bertillon measurements were close enough to identify them as the same person. However, a fingerprint comparison quickly and correctly identified them as two different people. (Per prison records discovered later, the West men were apparently identical twin brothers and each had a record of correspondence with the same immediate family relatives.) **Fox, Albert Ebenezer and Ebenezer Albert** The Story of the Fox twins is the English equivalent to the William and Will West story in the United States. The Fox twins were born in St. Ippolytes, England and recognized as poachers and petty thieves who accumulated over 220 convictions between them. Sgt. John Ferrier is said to have used this case as an example at the 1904 World\'s Fair to show how the Bertillon system wasn\'t sufficient for identification but the Fingerprint System prevailed. **TYPES OF FINGERPRINT PATTERNS** c\. Double loop 1. Lateral pocket loop 2\. Twin loop d\. Accidental Whorl/Pattern **3 Phalanx/phalange of finger** basal phalanx - the one nearest the wrist, middle phalanx, terminal phalanx -- where you can locate the fingerprint patterns **CHARACTERISTICSOF MAJOR FINGERPRINT PATTERNS** **ARCHES** No delta No core Ridges flow from one side to other side **LOOPS** 1 delta 1 core Sufficient recurve **WHORLS** Two deltas 1 or 2 cores Complete circuit or sufficient recurve **ARCHES** **LOOPS** **WHORLS** **Cuspal** When the ridges on a finger run vertically from the crease to the tip of the finger. Moenssens states that these patterns cannot be grouped into any of the Henry pattern types. Cummins states that they should be grouped into the accidental whorl category. Others have stated that cuspal patterns should be classified as a tented arch.[\ ] **[FORMS OF DELTA]** A bifurcation An abrupt ending ridge A dot A short ridge A meeting of two ridges A point on the first recurving ridge located nearest to the center and in front of the divergence of the type lines. **When there is a choice between two or more possible deltas, the following rules govern;** 1\. The delta may not be located at a bifurcation which does not open toward the core. 2\. When there is a choice between a bifurcation and another types of delta, the bifurcation is selected. 3\. When there are two or more possible deltas which conform to the definite, the one nearest the core is chosen. 4\. The delta may not be located in the middle of a ridge running between the type lines toward the core, but at the [nearer end only]. The location of the delta is this case depends entirely upon the point of origin of the ridge running between the type lines toward the core. **B. [CORE]** -- is the appropriate center of the finger impression. **[SELECTION OF THE CORE OF A LOOP]** 1. The core is placed upon or within the inner most sufficient recurve. 6\. In case of interlocking loops at the center, two loops are considered as one.