The new tenants at 669 Cheryl Dr. mowed their lawn and decorated for the holidays, waving to passing neighbors in their quiet pocket of Warminster. They were friendly, neighbors said, if not sociable.

But it was all a facade, authorities said, a thin veneer of suburban normalcy camouflaging a sophisticated heroin operation in the home’s basement that raked in $8 million a week by pushing out hundreds of pounds of the narcotic.

On Thursday, it became more clear how the drug ring conducted its business in plain sight for months. From having someone else rent the property to squeezing SUVs into the home’s tiny garage, to load them up with trash bags that investigators believe were filled with heroin, the 11 members of the drug ring were careful, law enforcement officials said.

As those details came into focus, the members of the alleged drug crew, arrested Tuesday, sat in the county jail, unable to post bail, according to court records. The ringleaders, identified by theBucks County District Attorney’s Office as Moises Rodriguez, 42, of Paterson, N.J., and Dariel Vasquez, 38, of Northeast Philadelphia, are each being held on $10 million bail.

The nine others each face bail of $5 million. All 11 have been charged with felony drug distribution and related offenses.

“They knew how to behave, how to blend in,” said Marion McLauchlan, who has watched neighbors come and go for more than four decades from the home she shares with her sister on Cheryl Drive. “You don’t think this could happen here, but apparently, there’s always a possibility.”

On Tuesday night, McLauchlan watched a new kind of commotion: Nearly 20 police vehicles, including large vans carrying federal agents, descended on the block. Explosive charges shredded a front window and rear door as officers stormed the home in the culmination of a months-long investigation.

When they emerged, the 11 people had been taken into custody, handcuffed and lined up on the lawn, covered in blankets to ward off the December cold, according to McLauchlan.

Bucks County District Attorney Matthew Weintraub said Thursday that it was too early to determine how far the crew members spread the heroin they packaged at the home, or where the drugs originated. Some of the stamps on the 200 pounds of heroin and fentanyl recovered Tuesday were known to his investigators from earlier drug seizures, with names like “Black Panther,” “Wild Wolf,” and “Domino.”

But Weintraub acknowledged that the location of the operation came as somewhat of a surprise to his office.

“It’s always been my understanding that an operation like that occurs elsewhere, predominantly in Philadelphia, which we’ve been trained to know as a hub for the drug trade,” he said. “But I take nothing for granted. If it’s happening here, we want to know about it, and we want to stop it.”

None of those arrested in the raid have criminal convictions in Pennsylvania, according to court records . However, law enforcement sources said Thursday that they were probing the possibility that some of the suspects may have been previously arrested under different names.

Investigators were led to the home on Cheryl through an anonymous tip in July, about two months after the new neighbors moved in. Weintraub said a task force of local, county, and federal officials kept a close eye on the house through the summer and fall, but declined to elaborate.

The search warrant approving the raid was issued by U.S. Magistrate Judge Marilyn Heffley, but it has been placed under a federal seal, a spokeswoman for the FBI said. So, details of the evidence investigators gathered were few.

From where Steve Puglisi sits, something seemed off when the new tenants moved into the house in April. On his street, where block parties are a staple and everyone stops to say hello during evening walks, the people at 669 stood out.

“I figured, if they were transient, they wouldn’t be too friendly, because they knew they’d be moving soon,” said Puglisi, whose home is directly across the street from the alleged drug operation site.

Then he noticed small details, like the way they’d cram large vehicles into the garage, sometimes even scraping the side panels on the walls. Or the way they’d block the windows.

“Sure, we suspected something like this, but we never thought it was that scale,” Puglisi said. “No one would drive up at night for pickups and leave, like you’d expect.”

On Thursday morning, the home still bore the scars of the police raid two days earlier. Unlit Christmas lawn ornaments sat in stark contrast to the cracked window frame, out of which a curtain stirred listlessly in the slight breeze.

Property records show that the house is owned by Vera Maydel, who purchased it in 2007. Years earlier, it was owned by Patricia Stephens, a township supervisor. Neighbors said Maydel began renting out the house a few years ago, after the death of her husband made it difficult to pay the mortgage.

Maydel’s daughter visited the home Thursday, leading a team of contractors who secured its door and windows with broad pieces of plywood. She declined to comment at length, saying only that her mother “thought everything about the renter looked good.”

Vladimir Shursky, the Realtor who helped Maydel find a tenant for the home, said he was first approached this spring by a woman through the real estate website Zillow. Shursky declined to identify the woman, but said she was not one of those arrested.

During the application process, Shursky ran what he called a standard background check on the woman, including reports on her credit, eviction history, and criminal background.

“Everything came back clean,” he said Thursday. A lease was executed April 1 for $2,600 a month.

Shursky said the tenants never complained to Maydel about any issues, and that she only visited the home once since they moved in, to check on the pool in the backyard.

There was never any indication, he said, of what was going on inside.

“Ours is a neighborhood where you’re almost sure something like this won’t happen,” Puglisi said.