The French doors were cracked open to the night outside, and someone was down in the kitchen. Ryan Drummond, standing noiselessly at the top of the stairs, was sure he knew who it was.

Grasping a frame with a picture of his wife and children — the only possible weapon at hand — Mr. Drummond, 42, ran through his options. He decided: best to let the intruder understand that he knows he’s in the house. He flicked the lights on and off.

A terrifying moment passed.

Then the lights flicked back in response.

For nearly a week since a convicted murderer slipped away from the Chester County Prison, the people in the area, a quiet stretch of farmland and wooded thickets about an hour’s drive outside Philadelphia, have had to live with a relentless unease. Teams of police officers jog through backyards, drones buzz in the skies, and for a time, helicopters shuddering overhead blared the sound of a woman’s voice pleading in Portuguese — the mother of the man who escaped, begging, in a recording, for him to give himself up.

The fugitive, Danelo Cavalcante, 34, was convicted on Aug. 16 of stabbing his former girlfriend, Deborah Brandao, nearly 40 times, killing her in front of her children. On Aug. 22, he was sentenced to life in prison. Last Thursday morning, a little over a week after the sentencing, he disappeared.

In a news conference on Wednesday, Howard Holland, the acting warden of the prison, described for the first time how Mr. Cavalcante escaped. A little before 9 a.m., while a basketball game was going on outside in the exercise yard, he said, Mr. Cavalcante crab-walked up two parallel walls — putting his hands on one wall and his feet on the other and quickly climbing to the roof, a feat captured on video that was shown at the news conference.

He pushed through two installations of razor wire, some of which was put in after another inmate escaped by the same route in May, and scaled a fence before making his way off the prison grounds. The earlier escape was thwarted within minutes when a corrections officer in a watchtower saw the person fleeing and sounded the alarm. But this time, the officer in the tower, for some reason, did not see Mr. Cavalcante, whose absence was discovered by officers in his cell block nearly an hour later. Mr. Holland said the Pennsylvania attorney general’s office was investigating the escape.

Mr. Cavalcante has been seen in the seven days since, once by a prison employee, several times in the ghostly infrared light of security cameras and most recently, said Lt. Col. George Bivens of the Pennsylvania State Police, by a resident who spotted him on Tuesday evening in a creek bed, heading into the woods. The police arrived on the scene but were unable to track him, Colonel Bivens said, after a search dog suffered a “heat related emergency.” Because of that sighting, he said, authorities have once again expanded the area they are searching, which initially seemed to be narrowing but has broadened and shifted in recent days.

For many residents, Mr. Cavalcante has been an unseen presence dominating their daily lives, creating as much of an inconvenience as any sense of panic. Businesses have had to lock their doors, minor errands have entailed navigating roadblocks and TV news trucks and armed police officers have greeted residents in their driveways.

“It’s like our whole life is shut down over here,” said Kristin Muzik, 50, who stopped at a convenience store on Wednesday afternoon with her three children, whose schools were closed for a second day. “I really hope they catch him quickly.”

Few, if any of them, have had an encounter like the one Mr. Drummond had on Friday evening.

Credit…Chester County District Attorney’s Office, via Associated Press

Mr. Drummond, who gave his account first to WPVI-TV, the local ABC affiliate, said he was “100 percent” sure it was Mr. Cavalcante who had been in his house, having seen his image in the news.

At a news conference on Saturday, while discussing possible break-ins related to the escape, the Chester County district attorney, Deb Ryan, said that a homeowner had thwarted an attempted burglary in the area on Friday evening, and that authorities had a “strong belief” that the intruder was Mr. Cavalcante. The Pennsylvania State Police would not discuss the incident.

The week had come to an unsettling close for the Drummond family, who live about a mile and a half from the prison. News of the prison break sent recess indoors at the local schools and as she got ready for bed, Mr. Drummond’s 9-year-old daughter asked her father nervously about the French doors that didn’t seem to lock right. He reassured her, asking her why, of all the doors in the area, the fugitive would choose to try those.

He would later wonder if someone had been listening at that moment, perhaps just outside the window or in the shadows beneath the deck, where the family had spent the evening.

Hours later, he awoke to sounds downstairs.

“‘I don’t want to freak you out,’” he recalled whispering to his wife. “‘But I think someone is in the kitchen.’”

He got out of bed and walked softly to the bedrooms of his three children, making sure they were still asleep. Then he came to the upstairs landing, where he saw — exactly as his daughter had feared — that the French doors stood cracked open. That is when Mr. Drummond and the man in the kitchen communicated by the flicking of light switches.

Telling his wife to call the police, Mr. Drummond braced for a potential confrontation, then watched as the man walked to the French doors, carrying a bag and appearing to be in no particular hurry. The police came within minutes, he said, and rushed to the tree line, but the man was gone into the night.

All that the man apparently took was a peach, an apple and a handful of snap peas that Mr. Drummond had bought at the farmers’ market earlier that day and had laid out on the counter.

For the rest of the weekend, the family tried to live as ordinary a life as possible, fixing soccer nets and having drinks with neighbors as SWAT teams came in and out of the woods and helicopters hovered overhead. Things have quieted down on their block since Monday night, when it appeared that Mr. Cavalcante had slipped out of the area where the police had been focused. But there is no true return to normal in the area as long as the manhunt continues.

“I walk every morning for five miles,” said Susan Smith, 64, who lives nearby in Unionville. “Today, I took bear spray, just in case.”

Ms. Smith acknowledged how uneasy the past few days had been but she said that it was important to keep the disruption in perspective. An hour away in Philadelphia, she pointed out, there were neighborhoods where fear of violence was a constant fact of daily life.

“We’ve had to amend our behavior a bit,” she said. “But we know this too will pass.”