A Santa Rosa man was in custody Tuesday following an investigation into a sophisticated marijuana growing operation hidden behind a false wall at his car stereo installation business.

Santa Rosa narcotics officers arrested Lance Guyan, 29, at his home Monday afternoon, Sgt. Chad Heiser said.

Officers raided Guyan's Audio Legends business off Piner Road on Feb. 21.

Guyan had maintained the plants growing in the back of the business were legal, according to the building owner.

But narcotics officers determined Guyan was growing the plants to sell, Heiser said.

"There are indications that he is running a for-profit marijuana operation," Heiser said.

On the day of the raid, it took officers about 15 minutes to get through a fortified front door of the locked, unoccupied business, Heiser said.

Inside, they found a false wall along the back of the shop. A door through the wall was concealed behind a large, rolling cabinet.

Behind the wall were three rooms and 140 plants, half of them around 5 feet tall.

The area was fully vented and lighted by grow lights powered by car stereo amplifiers.

While officers determined Guyan's garden was illegal, they found a second business in the building with an indoor marijuana garden was legal and left it in place.

Owners there had paperwork indicating they were operating as a legitimate medicinal marijuana co-op, said Heiser.

Guyan was in Jamaica at the time of the raid, Heiser said. Officers confiscated several thousands dollars in cash at the business and hundreds of rounds of ammunition. They also impounded six vehicles, including a motorcycle, classic car and several off-road vehicles.

Additional marijuana plants were discovered in Guyan's home on Miles Avenue in southwest Santa Rosa when officers served a search warrant later on Feb. 21, Heiser said.

Guyan was arrested on suspicion of three felony counts including cultivating and possessing marijuana for sale. His bail was set at $70,000.

Guyan's Facebook page indicated he was a 2001 Point Arena High School graduate and had owned the car stereo installation business since 2007.