456, 2008 SCC 18, is a constitutional decision by the Supreme Court of Canada on the limits of police powers for search and seizure.

On January 25, 2002, at about 11:00 a.m. at the Calgary, Alberta, bus terminal, three police officers were involved in a special operation designed to detect drug couriers.

The following issues were put to the Court: All nine judges agreed that the dog sniff of the passenger's bag at the bus station amounted to a search within section 8 of the Charter.

McLachlin CJ and Binnie, LeBel, Fish, Abella and Charron JJ agreed that the sniffer dog search of the passenger’s bag at the bus station violated section 8 of the Charter and that in the circumstances of this case, the evidence should be excluded pursuant to section 24(2) of the Charter.

In determining whether the police were authorized at common law to conduct the search in fulfillment of their general duty to investigate crime, the threshold for the exercise of police powers should not be lowered to one of "reasonable suspicion", since to do so would impair the important safeguards found in section 8 against unjustified state intrusion.

The sniff in this case was an unreasonable search since the RCMP officer did not have grounds for reasonable suspicion at the time the dog was called.

However, because of R. v. MacKenzie, [2013] 3 SCR 250, 2013 SCC 50 (CanLII), police can now simply draw on their experience in the field to create broad categories of “suspicious” behaviour into which almost anyone could fall.

They found that the dog sniff of the passenger's bag at the bus station amounted to a search under section 8 of the Charter.