Sonya Bell-Jacobs grabbed some cookies and Coke and snuggled in for the night. She likes to fall asleep to the flickering light of the TV in the den, and that’s where she was when someone took the garage door opener from the car parked outside, pressed the button and walked into her house.

The intruder grabbed her purse with black tassels, her husband’s wallet and BlackBerry, and the car keys sitting a couple of feet from her. It wasn’t until morning, when her husband asked whether she moved his phone, that the family knew a burglar had been there.

Over several months, Montgomery County police said, criminals crept into more than 20 houses in Germantown and Gaithersburg while the residents were inside, stealing phones, credit cards and cars. Last week, authorities indicted Marcus Antonio Lee, 20, in four of the burglaries and in another attempt, and say he is a suspect in others. He denies involvement.

Although police say the latest rash of incidents stopped with the June 20 arrest of Lee and others, the effects are lasting.

“It’s a pretty nice neighborhood,” Bell-Jacobs said, “but now it’s just been tormented.”

She still falls asleep on the couch, but keeps the lights on most of the night and constantly peers out the windows. Another woman whose home was hit has had trouble sleeping and is considering moving her family.

Bell-Jacobs said people in her neighborhood are keeping an eye out for each other. But her husband, Roderick, said the deeper change is how they’re keeping an eye on anyone they don’t recognize.

“Just call it what it is,” he said. “I look at people differently. Even somebody walking through. I’m sorry. It may be profiling or whatever, but I watch ’em. ‘Where you going?’ . . . I look at everything now.”

While yearly homicide totals in Montgomery hover in the teens, burglaries come in the thousands. They’ve dropped 15 percent since 2008, but the county still had 3,061 burglaries of homes and businesses last year. That’s less than the 3,953 in the District, but three times the total in neighboring Fairfax County, the more populous suburban county Montgomery compares itself to.

Days after the intruder left the Jacobs’s home and drove off with their new Hyundai and a State Department ID, Steven Fallow was sleeping in his townhouse a couple of miles away.

A burglar came through the kitchen window and stole Fallow’s PlayStation game system and his 2001 Honda Civic. Police say Lee was at it again.

Fallow, 32, spends his time working at Best Buy, exercising at the gym and going to night school, not worrying about latching the kitchen window. He counts himself lucky that the intruder didn’t enter his bedroom. “It was really my fault,” he said. “I don’t feel less safe. If the window was locked, nothing would have happened.”

Authorities have indicted Marcus Antonio Lee, 20, in four of the break-ins and in another attempt, and say he is a suspect in others. (MONTGOMERY COUNTY POLICE)

That was not Monika Puchala’s reaction. The single mother and Polish immigrant lives next door and works as a lab technician at MedImmune, the Gaithersburg biotech firm. She and other neighbors offered Fallow rides to work before police recovered his car.

She has become uneasy in her own neighborhood. “Your whole evening changes when you come home from work. . . . You become more on defense,” Puchala said. She’s also worried about her outgoing 10-year-old daughter.

“She speaks to people. She waves,” Puchala said.

Her message for her daughter: “Do not speak to anyone.”

Her message for those responsible: “If your mom or dad have not made it clear, let’s make it clear: You have no right to do that.”

Lee, who police say sports a Jesus tattoo on his forearm, has been jailed for burglary before.

In March 2011, he tore a screen and unlocked the back door of a home near the Jacobs residence. A woman inside woke up and screamed when she saw him, and he ran out with a pack of cigarettes and a laptop, authorities said. During a court hearing after his arrest, his lawyer appealed to the judge.

Lee’s grandparents raised him, and after his grandmother died in 2007, he was his diabetic grandfather’s caregiver until the man died, the lawyer said. Lee was evicted and left to fend for himself as a teenager, she said.

“I have no excuse for anything,” Lee told the judge last July. He said he was eager to “get back out there so I can just hustle hard, so I can just basically get back on my feet. I don’t have no one to provide for me.”

He and the judge talked about the possibility of Lee joining the military, and Lee said he was considering it. But he also heard there are jobs on cruise ships, he told the judge, where he could “have a free place to sleep, free food, and just having work experience.”

He was sentenced to three years, with two suspended, and was on probation when he was arrested last month. Authorities said he was an opportunist who sought out unlocked doors and windows. He drove the stolen cars around Germantown and was nearly nabbed driving one in the District, police say.

Police searched the Germantown home he shared and found sets of keys, a garage door opener under the couch, a couple of navigation devices and an AK-47 magazine, according to police documents.

At a court hearing last month, Assistant State’s Attorney Stephen Chaikin called Lee a “one-man crime wave that recruits other people.” Three others were arrested in connection with the burglaries, including a minor, but authorities said Lee was the leader.

A public defender assigned to one of Lee’s cases did not return phone calls.

Police were worried that the crimes might lead to a confrontation, but the arrests came before anything of that nature occurred. “We were very blessed in that regard,” said Capt. Luther Reynolds, who helped oversee the investigation. He said the frequency and boldness of the crimes had been rising, and “we’ve had zero since then.”

Montgomery Police Chief J. Thomas Manger said Montgomery’s burglary numbers are higher than in Fairfax, where he had been chief, because Maryland’s sentencing guidelines are more lenient than Virginia’s. The commonwealth abolished parole in 2004, and in Maryland burglars and other criminals often get out of prison after serving just a fraction of their sentence, Manger said. He views burglaries through the lens of his own family. If one ever happened in his home, “my daughter would never be able to sleep again,” Manger said.

Police and prosecutors say they are redoubling efforts to reduce burglaries, by using cell tower records, social media, DNA analyses, red-light camera images and more traditional interviews. They said 90 percent of offenders are 25 and younger, and nearly 80 percent live in Montgomery.

For some residents, though, those efforts may have come too late.

Zheng Zhaoyan works at an air conditioning company, but her extended family (brothers, four children and a grandmother) likes to save money by keeping the windows open and a breeze flowing.

When family members forgot to lock the front window of their Gaithersburg home on June 19, police say Lee let himself in.

While Zheng’s husband was in the shower and she was sleeping, the burglar came into her bedroom and stole an iPhone, a designer purse, a pair of wallets and keys. When she heard the garage door opening, she looked out and saw the thief driving away.

She’s worried that someone will break in again, and keeps thinking about how comfortable the intruder seemed.

“They are not afraid of people, even [when] there’s a whole bunch of people living in the house, they just broke in without any care about it. It’s terrible,” she said. She’s felt safe living there for more than eight years. Not anymore. “For me, I’m thinking about moving. For my family’s safety, I’m thinking about that.”