Police were investigating two sophisticated marijuana-growing operations in San Jose discovered by San Jose city firefighters sent to put out fires in vacant residences over the past several days.

"The (growing) systems have been described as elaborate," San Jose police spokesman Officer Albert Morales said.

So far, detectives do not yet know who ran the grow houses, one discovered Sunday night and the other on Wednesday, because the cultivators who rented the homes gave false identity information to property managers, Morales said.

For police, when someone uses fraudulent driver's licenses, Social Security numbers and other identifiers, "it becomes a chase that leads to nowhere," Morales said.

The two pot growing operations do not appear to have been run by the same people, Morales said.

The latest pot grow house finding came at 11:45 p.m. Sunday, when firefighters answered a reported fire in the garage of a house in the 500 block of Scottsville Ct in East San Jose near North King Rd.

Firefighters doused the blaze in the garage and uncovered an intricate marijuana growing setup in the home, fire Capt. Reggie Williams said.

The operation included potted plants on the floor, tin foil-like material lining the walls and large illuminated light bulbs to imitate sunlight, Williams said.

"It looked like a manufacturing facility -- very, very, high-tech," Williams said.

Whoever ran the grow house used electrical wiring that bypassed a PG&E meter in the garage, creating heat that probably ignited the fire, Williams said.

"It was definitely electrical-related," he said.

Police confiscated about 300 pot plants from the home on Scottsville Ct, Morales said.

The other pot grow house fire took place at 3:15 p.m. Wednesday, when San Jose firefighters responded to flames at a single family home in the 1800 block of Fumia Place near Oakland Road in North San Jose.

The two-alarm fire caused major damage to the two-story house and at some point, the second floor bedroom collapsed into the living room.

Inside the rented residence, firefighters observed an indoor marijuana cultivation establishment that San Jose police later said included about 80 plants.

Firefighters found no people or furniture in the two houses, only the pot operations, Williams said.

"It's people who rent them out for grow houses," he said.

While the fire on Fumia Place was still being investigated Monday, evidence shows that it started on the second floor where high-wattage heat lamps were turned on over growing plants, Williams said.