Crime Scene Evidence PDF

PROTECTING A CRIME SCENE AND HOW TO COLLECT EVIDENCE CANADA’S POLICE FORCES Canada’s police forces cost about 16 billion dollars in 2019, with over 66,000 officers total at three different levels, federal, provincial, and municipal. RCMP was formed in 1873, make up the fed...

PROTECTING A CRIME SCENE AND HOW TO COLLECT EVIDENCE CANADA’S POLICE FORCES Canada’s police forces cost about 16 billion dollars in 2019, with over 66,000 officers total at three different levels, federal, provincial, and municipal. RCMP was formed in 1873, make up the federal police force. They serve as provincial police in all provinces and territories except Ontario, Quebec, and Newfoundland and Labrador. Can also serve as municipal police. FEDERAL POLICE FORCE  In the territories, the RCMP is the only operating police force, unless Aboriginal forces are established.  RCMP is responsible for all federal law under the Criminal Code, cover four areas: o Border Integrity o Drugs and Organized Crime o International Policing o Financial Crime PROVINCIAL POLICE FORCE (ONTARIO)  We have the OPP (largest provincial force), Quebec has the Surete du Quebec, and Newfoundland has the Royal Newfoundland Constabulary.  OPP is responsible for: o Policing municipalities that are not required to maintain their own police force o Responding to municipal police requests for emergencies o Traffic control on all 400-series and major highways o Providing investigative services to the coroner’s offices and other ministries o Provincial firearms registry, security at Queen’s park, protecting Ontario government officials, etc. MUNICIPAL POLICE FORCE Municipal police have jurisdiction in their towns and cities. They fund their own police force. Smaller communities (like Kingsville’s) use the RCMP. Organized into numbered divisions that serve the community. These divisions are divided into specialized squads (Gang Crime Unit, Robbery Squad, Homicide Squad, Explosives Disposal Unit) Duties can include: o Preserving the peace o Preventing crimes from occurring o Assisting victims of crime o Apprehending criminals o Laying charges and participating in prosecutions o Executing warrants o Enforcing municipal bylaws FNMI POLICING First Nations Policing Policy is a partnership between federal and provincial governments and the FNMI peoples to develop police services for native communities. Goal is to offer services that are professional and in touch with the culture and needs of the community. (Dakota Ojibway Police Service established in 1977) Good case to discuss: https://jurisprudence.reseaudialog.ca/en/case/r-v- decorte/ Crime Scene  CRIME SCENES  Crime scene: the site where the offence took place. Three tasks to perform: o Call an ambulance and assist injured people at the scene o Call reinforcements to help eliminate any hazards o Officers must continue to search the crime scene even if witnesses say the suspects have left.  To protect the crime scene, officers must accurately establish two boundaries, the centre and the perimeter.  CENTRE AND PERIMETER  Centre: the area in which the offence was actually committed.  Perimeter: the areas surrounding the centre, where the offender may have been present or may have left evidence.  Crime scenes are preserved for three reasons: o Allow for a thorough search of the scene o Seize and collect physical evidence o Ensure that the physical evidence seized is admissible in court.  Evidence can be contaminated if mishandled.  Contamination: the loss, destruction, or alteration of physical evidence.  To avoid that, officers need to protect and preserve evidence.  They keep a police log (a written record of what an officer has witnessed). These can help with officers recalling events, especially when they testify at a trial.  INVESTIGATING A CRIME SCENE  Four types of police officers investigate a crime scene, and they all have a different role. o Patrol offi cer has a “beat” or an area that they check regularly (usually the first member of the department to arrive at a crime scene – secure the crime scene with yellow tape) o Scenes of crime offi cer is trained in evidence collection and preservation techniques o Criminal identification offi cer is responsible for searching the crime scene, examining the scene for physical evidence, gathering and analyzing evidence and sending certain types of evidence to a lab. o Criminal investigations bureau offi cer is a plainclothes detective with experience in a particular area of crime ARRIVING ON THE SCENE Role of a Police Officer: 1. Assist the injured 2. Call for reinforcements to eliminate hazards 3. Search for perpetrators 4. Secure the scene 1. Center of the crime scene 2. Create a perimeter 3. Avoid contamination and create a police log CSI IN REAL LIFE – CLICK ON THE LINK Crime Scene Investigation – Behind the yellow line.  EVIDENCE Physical evidence: any object, impression, or body element that can be used to prove or disprove facts relating to an offence.  More important than evidence obtained through witnesses’ statements. Forensic science: the use of biochemical and other scientific techniques to analyze evidence in a criminal investigation.  Pathologist performs an autopsy to determine how and when a person died.  There are scientists who specialize in firearms and are able to analyze bullet fragments to identify the type of gun used in a crime.  RECORDING A CRIME SCENE Exact Measurements Photographs Labelling DNA TESTING DNA testing as a tool for criminal investigations has only been used in the last 20 years. The technology has improved The most common substance used for testing is blood, but hair shafts, mucus, skin samples, salvia and semen are used as well DNA testing is still slow and it’s still expensive. It’s not the first tool used to narrow down a suspect pool but it is often used to affirm that a person is the perpetrator There are different methods of testing but the two common are PCR(very advanced) and RFLP BLOOD SPATTER AND TYPING Blood spatter can tell us a lot about what happened at a crime scene. Based upon the spatter patterns, we can determine if an artery was severed, if the person was bludgeoned in the head, how they were stabbed or if their neck was sliced open Using trigonometry and calculus, scientists can also determine how tall the perpetrator was and which hand they used to harm the victim. Scenes of Crime Identification officers will take photos of the crime scene and then analyse Arterial Spray Degree of Directionality GUNSHOT RESIDUE When a gun is fired, the cartridge sprays minute amounts of explosive primer(gunpowder) propellant and even minute particles of the metal cartridge onto the person holding the gun. There are two types of GSR tests. One is for clothing and is called the Modified Griess test. It tests for nitrate residue that is expelled from smokeless gunpowder The second is the one we see on TV. It tests for lead residue and is called the Sodium Rhodizonate Test. It’s the one that turns pink then blue. ANGLE OF GUNSHOTS Determining the angle of the gunshot can give clues as to where the shooter was standing, and how tall the shooter is Using trigonometry and other fun math, technicians can determine a lot of information. They use laser sights, rulers and dowels to determine the trajectory of the bullets. This can rule out a suspect or identify someone as the person who pulled the trigger CALIBER TESTING Caliber testing refers to matching the markings made on the casings or bullets that have been fired to the gun itself to match the gun as the murder weapon. Testing occurs when a gun is fired into a testing chamber, the bullet is retrieved and then matched by the grooves made by the gun barrel. STAB PATTERNS/WOUND PATTERNS Every tool leaves behind markings and impressions. This holds true for weapons. Certain weapons will leave behind markings on the body. A serrated knife will leave behind jagged wounds. A straight blade won’t. Wound patterns are photographed and sometimes castings are made in order to compare with potential weapons being found later on. TIRE TREADS Tire treads are sometimes left in dirt, mud or snow at the crime scene There is a lot of info gleaned from a tire print: make and model of a car, how worn the tire is, and even how much weight the car was carrying when it made the print There are three types of prints: Visible(seen by the visible eye and often photographed), 3D( an impression made from plastic or plaster is cast) or Latent( not seen by the visible eye and made through static electricity) The technicians measure the print, photograph it, make models and then compare it to other tires in their records to determine its unique characteristics MARKINGS Markings are made automatically when tools or weapons touch a surface. Like stab wounds, the markings can indicate what tool or weapon was used For example, wire cutters used to cut a fence will leave markings on the part of the fence that act almost like a fingerprint. If that tool can be located, the technicians can match its markings to the ones at the scene of the crime Crowbar used to break and enter FIBRES When our clothing comes into contact with other cloth, fibres are transferred from one to the other. When we walk on carpet, we pick up fibres and transfer fibres Finding foreign fibres at a crime scene or on a body can give us clues as to who was at the crime scene Fibres are collected and then taken to the lab for analysis to determine what the fibre is made of and where it came from. If the police have a suspect that has access to something with those fibres, it may be evidence to prove the suspect was at the scene SEXUAL ASSAULT KITS This is a series of tests conducted at a clinic, hospital or doctor’s office that will be used as evidence in a sexual assault case. It’s sometimes called a “rape kit” or a SAFE( sexual assault forensic evidence) kit or a PERK ( physical evidence recovery kit) Some of the things that are collected are photos, swabs, DNA samples, fingernail scrapings, the victim’s clothing, and any other physical evidence left behind on the victim. FINGERPRINTS There are two types of prints-visible and latent. Visible are seen with the naked eye and can be prints made in dirt, oil or blood. Latent prints are not easily seen by the naked eye and will require some help in making visible PLANTS/ANIMALS Like fibres, plant tissue and animal hairs can transfer from one person to another or from one place to the crime scene Technicians can collect and then identify these samples to narrow down a pool of suspects.For example, if a piece of a rare orchid is found on a body, and one of the suspects has that orchid plant in their home, that can narrow down the suspect pool to that one person FOOTPRINTS Like tire treads, footprints can be visible or latent. Again, like tire treads, footprints can be photographed or have a plaster or plastic impression made of them. They can tell us the height of a person, their weight, how they walk-lots of details. Latent prints can be made by dusting electrostatic powder over where we think the print might be and raise the print to the naked eye. Sticky tape can be placed over it and the print lifted for scanning. AUTOPSY This is a full examination of the outside and inside of the body to determine cause of death and to record any evidence that helps solve the crime. A medical examiner or pathologist will conduct the autopsy. The outside of the body is photographed, hair is combed through, fingernails scraped and then a Y incision is made across the sternum and the body is opened. Organs are weighed and sometimes tested for toxins. Any injuries inside the body are catalogued. Bullets are retrieved and sent to ballistics for testing. REAL LIFE CSI? FORENSICS AND IMPRESSIONS GREAT FORENSICS WEBSITE YOUR TASK… Individually read pages 193-200 in your textbook to get a better understanding of different roles of individuals and components of a crime scene. Make notes on: Protecting and Preserving the Crime Scene Identifying and collecting physical evidence Procedures for labelling evidence On Page 201 Questions 1,3,4,5,6