Foundations of Criminal Investigation

First Response and Scene Preservation

When an officer is the first to arrive at a crime scene, their priorities are hierarchical. The immediate primary responsibility is the protection of life and property. Only after life-safety concerns are addressed does the priority shift to the preservation of the crime scene.

Preservation is critical because it prevents the contamination of the scene. Contamination can destroy or alter physical evidence, making it impossible for a "trier of fact" (such as a judge or jury) to make an accurate determination of what occurred.

Exam Tip: Remember the hierarchy of response: 1. Life/Safety $\rightarrow$ 2. Property $\rightarrow$ 3. Scene Preservation.

Witness Management and Legal Distinctions

Managing people at a crime scene is as important as managing physical evidence. Effective witness management involves making first contact to prevent contamination of their memory or the scene. Officers should collect personal and preliminary information but avoid detailed discussions or unnecessary conversation that might lead to "memory contamination". Furthermore, multiple witnesses should be separated immediately to ensure their accounts remain independent.

Distinguishing Roles

In investigations, not everyone who provides information holds the same legal status. It is vital to distinguish between these three roles:

Note: A Confidential Informant (CI) is a specific type of informant who has been granted an assurance of confidentiality by the police.

Evidence: Admissibility and Testimony

In a legal proceeding, the quality of evidence determines the outcome. According to Morris v. The Queen, nothing should be admitted into evidence unless it is relevant to the charge.

Admissible vs. Inadmissible

• Admissible Evidence: Facts that fall within a witness's own knowledge, observation, and experience.
• Inadmissible Evidence: This typically includes two categories:
  1. Hearsay: Evidence based on a statement the witness heard from another source, rather than their own direct knowledge.
  2. Opinion Evidence: Generally inadmissible because drawing conclusions is the job of the trier of fact.

The Expert Exception

While general witnesses are restricted to facts, expert witnesses are permitted to provide opinion evidence. Because they possess specialized expertise, they can provide opinions to assist the trier of fact in making correct judgments. However, even experts are prohibited from offering opinions regarding the mindset or intention of the accused.

Competence vs. Compellability

When a person is called to testify, two legal concepts apply:

1. Competence: The legal qualification to testify (e.g., being of sufficient age and mental capacity).
2. Compellability: The legal obligation to testify without excuse. Note that under Section 11 of the Charter, an accused is protected from self-incrimination.

Investigative Terminology: Interview vs. Interrogation

Precision in language is required when documenting investigative actions. While often used interchangeably in casual speech, they have distinct legal and procedural meanings:

• Interview: A structured, non-accusatory conversation used to elicit information from a witness, victim, or suspect.
• Interrogation: An accusatory process intended to elicit a confession from a suspect believed to be responsible for the offense.

Finally, the status of an individual changes as the investigation progresses:

• A Suspect is a "person of interest" suspected of a crime, whether they are under arrest or not.
• An Accused is a suspect who has been formally charged with a crime.

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