Crime Scene Evidence: Types & The Florida Evidence Code

• Crime Scene: location where a crime occurred, containing evidence, and can be a location, person, place, or object.

Evidence Rules & Concepts

• Evidence: anything that tends to prove or disprove a fact and is allowed in court.
• Proof: the effect produced by evidence.
• Florida Evidence Code (Chapter 90, F.S.): contains basic rules of evidence in criminal/civil proceedings.
• The Florida Evidence Code has 3 basic functions: to prove/disprove a crime, support/undermine other evidence, and determine an appropriate sentence.

Types of Evidence

• Direct Evidence: proves a fact without inference or presumption, conclusively establishing the fact.
• Indirect or Circumstantial Evidence: requires inference or presumption to establish a fact.
• It primarily forms the basis for most criminal cases.
• Other evidence types include Testimonial, Documentary, and Physical/Real.
• Testimonial Evidence: a witness statement that tends to prove/disprove facts, but is generally less reliable.
• Documentary Evidence: anything written/printed offered to prove or disprove facts.
• Physical/Real Evidence: actual objects offered to prove/disprove facts.
• Fruits of a Crime: objects obtained by the defendant because of committing the crime.
• Instrumentalities: items used by the defendant to commit the crime.
• Contraband: property that is illegal for a person to possess based on a statute/ordinance/rule.

Types of Physical Evidence

• Trace Evidence: Small quantities of material transferred from victim/suspect to each other or a crime scene.
• Microanalysis: Analyzing trace evidence with a microscope to determine the source of origin.
• Biological Evidence: Contains DNA.
• The most common examples are blood, seminal fluid, and saliva.
• Wet evidence should be air-dried and stored in breathable containers.
• Impression Evidence: Distinct marks on surfaces.
• Fingerprints:
• Patent: Form from friction ridges or corrugated lines on fingers.
• Plastic: Molded or embedded prints easily seen, created by touching an impressionable surface.
• Latent: Body residues left behind when friction ridges make contact with a surface. They should be photographed with a scale in RAW+JPEG format.
• Elimination: Used to distinguish prints belonging to victims/witnesses from possible suspects.
• Firearms:
• Secure the weapon, remove the magazine, and clear ammunition. Put ammo and magazines in separate containers
• Rifling: Grooves inside the barrel that provide unique characteristics, and nothing should be placed in the barrel.
• Electronic Evidence:
• Consider airplane mode or a Faraday bag.
• Riley v. California: Searching a cell phone without a warrant is unconstitutional unless due to LEO safety.
• Chemical/Toxicological:
• Most stem from DUI, sex assault, or death.
• PPE is essential.
• Secure strong chemicals in the trunk of the vehicle (like fentanyl).
• Questioned Document: Anything containing a mark to convey a message.
• Counterfeit money should be sent to the Secret Service (FCIC/NCIC - has database).

Admissibility of Evidence

• Admissibility of Evidence: Legal requirements that must be met before a jury can see/hear about evidence.
• Protects the defendant's constitutional rights, guards jurors from being misled/confused, and expedites the trial.
• Admissibility depends on whether the evidence was obtained legally, preserved properly (chain of custody), is relevant to the case, and is not unfairly prejudicial, confusing, or based on hearsay.
• Fruit of the Poisonous Tree: Doctrine where a court may exclude evidence from trial if the LEO obtained it illegally.
• Good-faith Exception Doctrine: If a LEO executes a search warrant believed to be valid and it's later determined to have a legal error, the court may still admit the seized evidence.
• Privileged Communication: The need to protect communications within certain relationships is more important than the admissibility of evidence (e.g., advocates/counselors and their victims).
• Private, protected, confidential disclosure cannot be forced.
• Perishable evidence: blood, footprints, tire impressions, trace evidence (can perish)
• Transitory evidence: can blow or wash away
• Fragile evidence: fragile - like a bullet hole in glass

Secure & Protect the Crime Scene

• The purpose of an investigation is to determine what happened during an incident, identify and locate the suspect, and develop enough evidence to establish probable cause for arrest.
• 1st priority: Secure, protect, and preserve the scene to avoid contaminating evidence.
• 2nd priority: Search for, identify, document, collect, and maintain physical evidence.
• When driving to the scene, consider the location, weapons, suspect's location, number of individuals, the number of LEOs required to contain/control the situation, additional services, special equipment, and special concerns/dangers.
• Secure scene - the size of the crime scene should be larger rather than smaller and depends on the type of crime, the type of evidence, and the location of evidence.
• Attempt to locate entry/exit points; look for signs like broken glass or pry marks.
• Do not allow any unauthorized removal/alteration of evidence.
• Protect evidence from weather, crowds, and unauthorized access.
• LEOs have the authority to arrest anyone who crosses marked areas after receiving a warning.
• Determine the property type.
• Public property: use and enjoyment of the public; generally open to the public.
• Private property: Belongs to an individual and is not open to the public. LEO can enter under exigent circumstances, to conduct a sweep for suspects, provide first aid, or if there's an indication that evidence will be lost, destroyed, or removed prior to acquiring a search warrant/consent.
• Designate a point of entry/exit.
• Assign an officer to the crime scene log to document the name, rank, agency, date/time, and reason for each person entering/leaving the scene. This provides proof of crime scene security and validates evidence collected.
• Document any contaminated/altered evidence.

Manage Victims, Witnesses & Suspects

• Identify all involved people: complainants, victims, witnesses, and suspects.
• Ask where they were and their degree of involvement/roles.
• Document names, DOB, gender, race, addresses, e-mails, and phones.
• Separate involved people.
• Keep victims, complainants, and witnesses separated in locations where they cannot hear one another.
• It helps focus on what individual each saw/heard and maintain the integrity of statements.
• Separating family may make the situation worse.
• Injured people:
• Look for/record the victim's injuries in detailed observations.
• Florida law allows officers to review footage from BWC.
• Ask fundamental questions: who, what, where, when, how, and why they were hit.
• Share information on the incident, scene, evidence, and people involved with your supervisor.

Document the Crime Scene

• Photographing is the first event.
• Photograph from general to specific:
• Overall: perimeter of the scene by framing an all-inclusive/four-corner view.
• Midrange: show the relationship between evidence items within the scene.
• Close-up: show details of a specific item of evidence, including a scale or identifier.
• Standard flashes project 9-12 ft.
• Photographic Framing: Compose photos to depict what you are trying to document.
• Overlap in overall/midrange shots to show relationships of items.
• Avoid bystanders, LEOs, equipment, and pets in photos.
• Oblique lighting: side lighting with a flashlight at a low angle to show details by creating shadows on the surfaces of impressions (shoe/tire impressions, tool marks) – and, use a flash
• Scale/Identifier: used to establish the original positions and draw attention to evidence; represent the size of the item with rulers, cards, coins, or dollar bills.
• Document both with case number, location, date/time, LEO name
• Suspect does NOT have the right to refuse photographic injuries
• Genital injuries: provide victim options regarding which officer will observe and photograph
• Document scene BEFORE and AFTER photographing or detailed work - aid in reconstruction, explanation, permanent recording of incident
• If sketching scene – do so after photographing and before any detailed work – helps show the position of objects not visible in photos.

Evidence Handling Procedures

• Employ a systematic approach to searching for evidence.
• Triangle of evidence: Identifies possible sources, connecting suspects and the victim to the scene.
• Chain of Custody: Document everyone who handled the evidence, as well as when, why, and how it changed.
• Documentation proves that evidence submitted in court is the same as that collected at the crime scene.
• It is a felony to alter chain of custody documents.

Follow Up Investigation

• Follow-up Investigation: Continuation of the initial investigation to determine if a crime occurred.
• Can also complete the investigation by identifying a suspect.
• Locate and review records of the initial or preliminary investigation to establish a case file.
• Compare list of victims/witnesses/suspects to ensure accuracy.
• Review listed evidence and identify what needs further processing.
• Identify witnesses not available for interview.
• Follow leads: Provides more information on a case that requires further investigation.
• Anonymous tips, confidential sources, social media, forensic analysis, surveillance, and statements.
• Include interviewing medical personnel/analyzing victim injuries.
• Field contact: Any person you have contact with while on patrol who does not necessarily generate an incident report.
• Document information in field notes.
• Confidential source: People who furnish police departments with information about crimes, generally for personal benefit or advantage (not civic duty).
• Document Confidential Informants: The type of confidential source recruited/managed by the LEO per the agency's policy.
• Modus Operandi (MO): Refers to HOW someone does something, usually repetitive.
• Identify crime patterns by identifying similarities in MO, type of scene, time/day, and 2+ crimes.
• Consider the Department of Correction's list of released inmates.
• Records:
• Private records: Privately owned businesses or organizations; not open to the public or LEO and require court orders to access them.
• Public records: Government entities and publicly owned utilities you may access on demand (social media).
• Juvenile records are restricted from public access but may not restrict LEO, may limit how information is used.
• Showup: Presenting a possible suspect to a witness for identification that occurs during the same time as the incident and near the incident/crime scene, so it is an immediate situation.
• Do not move the suspect to the victim/witness.
• It is suggestive by nature and not always reliable.
• The most effective way to visually identify a suspect is through videos/photos at the scene.
• Live lineup: A procedure that displays a group of people to a victim or eyewitness so that they can ID the perpetrator and eliminate suspects.
• Eyewitness: A person who can identify another person by sight as someone involved in a criminal proceeding.
• Photo lineup: A procedure that displays a photo array to a victim/eyewitness to ID/eliminate suspects.
• Photo array: A selection of photos compiled to show the victim/eyewitness in a non-suggestive manner to ID.
• A minimum of 6 photos.
• Filler photos: Photos of people other than the suspect that complete the array.
• Simultaneous presentation: When an independent administrator presents a group of photos to victim/eyewitness all at once (or, same time).
• Sequential presentation: When an independent administrator presents groups of photos to victim/eyewitness one at a time.
• Preserve the entire photo array as evidence.
• Lineup administrator: A person who conducts the lineup and is independent of the investigation.
• Unaware of which person in the lineup is the suspect.
• Neutral administration: Cannot see/track which photo the victim/eyewitness views until after.
• If none available, assume this role and use an automated program or randomly numbered/shuffled folders that contain the photos.
• Independent administration of eyewitness instructions:
• The perpetrator may/may not be in the lineup.
• The admin does not know the suspects' ID.
• You are not compelled to make an ID.
• Investigation will continue with or without an ID.
• Document, word for word, any comment.
• If there is no ID, document why.

Testimony

• Before a pretrial meeting, review all case documents and try to identify potential weaknesses.
• Discuss with the State Attorney's Office (SAO) to identify/understand areas of weakness relevant to testimony and clarify concerns.
• Testimony is given in a judge's chamber, attorney's office, or witness stand.
• Rule of Sequestration: Forbids anyone who will testify from discussing any aspect of the case with anyone but the involved attorneys.
• Invoke/impose "the rule."
• You must never communicate with a juror.
• Take the oath provided by the clerk of court, court reporter, judge, or designated court personnel.
• Avoid:
• Enhancing testimony.
• Displaying the appearance of prejudice (destroy credibility).
• Using police jargon.
• Speaking in a monotone speech.
• Addressing the defense attorney as a public defender because it shows the defendant can't afford counsel.
• The following questions are objectionable and are where you must make an objection
• Someone to make a conclusion.
• Irrelevant questions.
• Beyond the proper scope of questioning.

Cross Examination Tactics

• If they project the impression that you are inept, convey professionalism/decisive answers.
• If they appear confrontational or badgering, pause/stay calm and remember the motive.
• If they fire rapid fire questions, ask for a repeat of the questions.
• If they lead you to say you are expert, stay alert/control ego, focus on the facts, and don't get confused.
• If they mispronounce your name and you lose concentration, politely correct them first, then ignore them.
• If they draw a conclusion or assumption, correct inaccurate facts and focus on facts without opinions.
• If they demand yes or no answers but you cannot answer with yes or no, then give facts.
• If they reverse or rephrase words, pay attention to what is asked; avoid agreeing to misstatements and correct errors.
• If they repeat or rephrase the questions, stay consistent and avoid frustration/restate the correct answer.