Police raiding an indoor grow-op in northern B.C. say that besides a wealth of marijuana, they also found three suspects hiding in a secret compartment in the building's walls.

Mounties searched a home on Rainbow Road in Quesnel on Tuesday, and discovered what they describe as a large grow operation comprising 2,591 plants spread throughout the entire space. It seemed that no one was at home, but a police dog that scanned the perimeter couldn't find evidence that anyone had left, either.

Investigators decided that the people responsible for the drug operation must still be somewhere inside the house, and say that a more intensive search revealed a hidden space between two walls. Three men were allegedly squirrelled away inside.

The 34, 35 and 37-year-old suspects, all residents of the Lower Mainland, are facing possible charges of production of a controlled substance and possession for the purpose of trafficking. They have been released from custody on a promise to appear in court.

Police say the drugs they seized during the raid have a street value of about $2.5 million. A pickup truck believed to have been used in the marijuana operation was also seized.