The fundamental legal articulation for a search incident to arrest (SITA) is often misunderstood. While we do, incident to an arrest, search the person for officer safety (and very important to do), that is the “why” (one of them), not the “authority”. The authority is derived from law. The Supreme Court of Canada has reaffirmed our authority for this “common law” power. In R. v. Caslake 1998 1 S.C.R. 51, at paragraphs 13 and 17 of the decision, the SCC ruled essentially that officers undertaking a search incidental to arrest do not require reasonable and probable grounds; a lawful arrest provides that foundation and the right to search derives from it. The right to search arises from the fact of the arrest. At paragraph 19, the SCC said that the three main purposes of a search incidental to arrest are: one, to ensure the safety of the police and the public; two, to protect evidence; three, to discover evidence. Taken one step further, at paragraph 22, the SCC ruled that if the justification for the search is to find evidence, there must be a reasonable prospect the evidence will relate to the offence for which the person has been arrested. Hence the difference between SITA a motor vehicle for a driver arrested for breach of probation versus one arrested for operating while impaired. In this example, the reasonable prospect will generally be lacking for the first, but there for the latter.
Also, at paragraph 53 of Cloutier v. Langlois 1990 1 S.C.R. 158, the SCC said in part, “…a search of the accused for weapons or other dangerous articles is necessary as an elementary precaution to preclude the possibility of their use against the police, the nearby public or the accused himself….Further, the process of arrest must ensure that evidence found on the accused and in his immediate surroundings is preserved. The effectiveness of the system depends in part on the ability of peace officers to collect evidence that can be used in establishing the guilt of a suspect beyond a reasonable doubt. The legitimacy of the justice system would be but a mere illusion if the person arrested were allowed to destroy evidence in his possession at the time of the arrest.”
The correct legal articulation for the, “Under what authority did you search my client” question is one of law, not “for officer safety” (different from investigative detention that was addressed in R. v. Mann 2004 S.C.J. No. 49); the, “Why did you search my client” question can be “for officer safety” (or two, to protect evidence; three, to discover evidence). Word play at its best, but important to know the difference.