TORONTO (AP) — Vian Ewart quickly figured out why police showed up at his elegant town house with a cadaver dog to search the waist-high stone planter at his doorstep. Ewart had for five years hired a burly landscaper named Bruce McArthur, who is suspected of being a serial killer, and police have set out on a grim search for clues that may be hidden across Canada's largest city. Like other clients of the landscaper, Ewart finds himself struggling to comprehend how the man who tended his planters and gardens could be someone the police say violently preyed on his sexual partners and killed at least five men over the span of nearly a decade.