Police in Calgary raided this northwest house and found a sophisticatd marijuana grow-op inside. ((CBC))

Tips from suspicious neighbours led Calgary police to raid a house in the northwest where they discovered a large-scale, million-dollar marijuana growing operation.

Almost 900 mature plants were seized — worth about $1.1 million — when police and members of the Alberta Law Enforcement Response Teams (ALERT) searched the house on the 200 block of Panamount Hill N.W.

Officers also discovered a sophisticated electrical-bypass system that was being used to siphon power for the grow-op, police said.

Thai Son Tran, 27, a foreign national living in Calgary, faces several charges including drug possession, manufacturing of drugs and theft of electricity under $5,000.

A search warrant was obtained after investigators followed up on complaints from members of the community about a car suspiciously driving in and out of the front garage at the residence.

There was also a strong marijuana smell coming from the house, police said.