BARRIE, Ont. - Police in Barrie, Ont., say they came across a booby trap when they busted a marijuana grow-op.

Investigators say one of the door knobs of the grow-op site was directly connected to an electrical panel in the house.

Police aren't sure if the trap was set for them or would be thieves.

Officers found 142 pot plants and some cannabis resin at the home on Coxmill Road on Thursday night.

A 42-year-old man faces a string of charges, including drug offences and setting a trap likely to cause harm.