Residents of an upscale Bellevue community are surprised and even scared after firefighters discovered a massive marijuana-growing operation in a neighbor’s home early Sunday morning.

Crews responding to a fire in the 16600 block of SE 70th Street – Cougar Crest – found a massive pot-growing operation that spanned nearly every room in the 4,000-plus-square-foot house, with grow lights, ductwork, fans, and 739 plants.

No one was in the home at the time of the incident.

The fire started with an electrical box in the garage, and a fire-suppression sprinkler system doused the small blaze before emergency crews arrived.

Firefighters forced their way into the two-story house to make sure the flames hadn’t spread. That’s when they discovered the grow operation.

Bellevue police identified the plants as marijuana, and the Eastside Narcotics Taskforce obtained a warrant to deal with the pot.

Bellevue Fire Department spokesman Lt. Eric Keenan says the find was unusual, noting that local firefighters have never encountered more than a few personal pot plants or mere marijuana odors during responses.

“Fore sure, we’ve never come across anything this big in firefighting before,” he said.

The case has some Cougar Crest residents fearing a return of the growers, and many are keeping a close eye on strangers who pass through the neighborhood.

“We’re more alert now,” said one resident. “We try to keep tabs on cars coming in and going out.”

The Reporter interviewed three residents for this story, and none would reveal their names for fear of being targeted for reprisal by the growers.

“Their actions are illegal, so we don’t know what their reaction will be,” said one woman, who claims that fear kept her awake all Monday night and forced her to take a day off work.

Police had made no arrests in the case as of Wednesday, and they did not answer questions about the suspects.

“The detectives are still in an active investigation and are following several leads and are not discussing any details yet,” said Bellevue Police spokeswoman Carla Iafrate in an e-mail.

The homeowner reportedly tried for several years to sell his house for as much a $1 million, but started renting it several months ago after failing to find a buyer.

Neighbors say the renters didn’t appear to fit the mold of Cougar Crest residents.

“It’s all professionals here, not anyone doing that kind of (drug) business,” said one resident. “Everyone leaves in the morning and comes back at night. These weren’t the normal people. I thought maybe they were in the bar or restaurant business and they worked at night.”

Residents say the tenants also kept to themselves – a rarity in their neighborhood – and had frequent visitors, most of them in their 20s and early 30s.

“There were lots of cars coming in, but they didn’t really socialize with the neighbors,” said one woman. “They didn’t seem to want to.”

Another resident said she thought the renters were perhaps throwing poker parties.

“It seems like something people do at their age,” she said.

The renters were gone late Saturday night when neighbors heard popping noises coming from the garage.

“I heard a firecracker sound,” said one resident. “I thought it was an early Fourth of July celebration.”

The popping grew louder shortly after midnight. Then there was smoke and water coming from under the garage door. Lights were also flickering up and down the block.

Several residents called 9-1-1.

Investigators say the popping noises came from electricity arcing in the house.

“They were powering so many grow lights, it just overloaded the circuit,” Keenan said.

Investigators found evidence that the growers rigged the home’s electrical system and bypassed safety features on the circuit breaker to draw more power.

“It looks like they were in there changing circuits or adding to them,” Keenan said.

Some residents in the neighborhood toured the house with its owner this week. They say it was drastically renovated to accommodate the grow operation.

“I was shocked,” said one resident. “I can’t believe it would happen here – that they actually pulled it off without anybody noticing.

“All of our neighbors trust each other. That’s why we live here. Now we’re all saying we have to be careful.”