Starting a Police Starting a Police InvestigationInvestigation

Law 120Law 120

Mr. DentonMr. Denton

Arriving at a Crime Arriving at a Crime SceneScene

The location or site where an offence takes place is The location or site where an offence takes place is referred to as the referred to as the crime scenecrime scene. When officers . When officers arrive, they have three tasks to perform:arrive, they have three tasks to perform:

1.1. Call an ambulance and assist any injured people at the Call an ambulance and assist any injured people at the scene.scene.

2.2. Call in reinforcements to help eliminate any hazards that still Call in reinforcements to help eliminate any hazards that still pose a risk (i.e. fire, bombs)pose a risk (i.e. fire, bombs)

3.3. Continue to search the scene even if witnesses says Continue to search the scene even if witnesses says perpetrators have left perpetrators have left

To protect people at the scene police must To protect people at the scene police must proceed as if the perpetrators are still there and proceed as if the perpetrators are still there and armed until they search the area themselves and armed until they search the area themselves and declare it safedeclare it safe

Protecting / Preserving the Protecting / Preserving the Crime SceneCrime Scene

The Crown’s success in prosecuting offenders often depends on The Crown’s success in prosecuting offenders often depends on the condition of the physical evidence taken from the scene of the condition of the physical evidence taken from the scene of the crime. the crime.

To protect the crime scene, the officers must accurately To protect the crime scene, the officers must accurately establish two boundaries: the establish two boundaries: the centrecentre and the and the perimeterperimeter. .

– The The centrecentre of the crime scene is the area in which the of the crime scene is the area in which the offence was actually committed. offence was actually committed.

– The The perimeterperimeter consists of the surrounding areas where the consists of the surrounding areas where the offender may have been present or may have left evidence. offender may have been present or may have left evidence. These areas include any entry or escape routes used by the These areas include any entry or escape routes used by the offender.offender.

Crime scenes are preserved for three reasons:Crime scenes are preserved for three reasons:– to allow for a thorough search of the sceneto allow for a thorough search of the scene– to seize and collect physical evidenceto seize and collect physical evidence– to ensure physical evidence seized is admissible in court.to ensure physical evidence seized is admissible in court.

Protecting/Preserving the Protecting/Preserving the Crime SceneCrime Scene

if evidence is not handled properly it may become if evidence is not handled properly it may become contaminated and be inadmissible in court.contaminated and be inadmissible in court.

ContaminationContamination is the loss, destruction, or alteration of is the loss, destruction, or alteration of physical evidence. This type of evidence is not admissible physical evidence. This type of evidence is not admissible in court and may lead police to draw inaccurate in court and may lead police to draw inaccurate conclusions.conclusions.

Investigators keep a Investigators keep a police logpolice log, a written record of what , a written record of what each officer has witnessed at a crime scene or has learned each officer has witnessed at a crime scene or has learned from questioning witnesses or suspects. from questioning witnesses or suspects.

Officers use their logs to document their daily activities. Officers use their logs to document their daily activities.

Later, these logs will help officers recall events, particularly Later, these logs will help officers recall events, particularly when they are called to testify at a trial. Investigators also when they are called to testify at a trial. Investigators also use photographs, sketches, and other recording techniques use photographs, sketches, and other recording techniques to document the evidence found at a crime scene.to document the evidence found at a crime scene.

Officers at a Crime SceneOfficers at a Crime Scene

Four types of officers investigate a crime scene and each Four types of officers investigate a crime scene and each has a separate and well-defined role to play.has a separate and well-defined role to play.

1.1. Patrol OfficerPatrol Officer – usually the first on the scene. Primary – usually the first on the scene. Primary duty is to secure scene and ensure no evidence is duty is to secure scene and ensure no evidence is tampered with or lost. Usually puts up yellow tape around tampered with or lost. Usually puts up yellow tape around the perimeter and conducts initial interviews with witness the perimeter and conducts initial interviews with witness at the scene. They also arrest suspects if the crime is in at the scene. They also arrest suspects if the crime is in progress.progress.

2.2. ““Scenes of Crime” OfficerScenes of Crime” Officer – Trained in evidence – Trained in evidence collection/preservation. Usually take photographs, lift collection/preservation. Usually take photographs, lift fingerprints and foot/tire impressions. They also collect fingerprints and foot/tire impressions. They also collect blood/hair evidence. These officers usually work on less blood/hair evidence. These officers usually work on less serious offences such as break and enter and car thefts.serious offences such as break and enter and car thefts.

Officers at a Crime SceneOfficers at a Crime Scene

3.3. ““Criminal Identification” OfficerCriminal Identification” Officer – Responsible – Responsible for searching the crime scene, examining scene for searching the crime scene, examining scene for evidence, gathering/analyzing evidence and for evidence, gathering/analyzing evidence and sending certain types of evidence to laboratories sending certain types of evidence to laboratories for analysis.for analysis.

4.4. ““Criminal Investigation Bureau” OfficerCriminal Investigation Bureau” Officer – – Plainclothes detective with experience in a Plainclothes detective with experience in a particular area of crime such as homicide, robbery particular area of crime such as homicide, robbery or sexual offences. These officers are trained to or sexual offences. These officers are trained to supervise the investigation, interview witnesses, supervise the investigation, interview witnesses, interrogate suspects, and draw conclusions from interrogate suspects, and draw conclusions from physical evidence and arrest suspects.physical evidence and arrest suspects.