Two school districts in Pennsylvania canceled classes on Tuesday as troopers searched by land and air for a convicted murderer who was spotted near residential areas after escaping from a prison near Philadelphia last week, the authorities said.

The fugitive, Danelo Cavalcante, 34, a Brazilian national, fled from the Chester County Prison on Thursday, days after he was convicted of first-degree murder in the April 2021 killing of his former girlfriend, whom authorities said he stabbed 38 times in front of her two children.

On Tuesday, investigators said they had expanded the search for Mr. Cavalcante because of several sightings just miles from the prison in Pocopson Township, adding that a reverse 911 call had been made to residents within a three-mile radius early on Tuesday. Police cars and helicopters were also playing a message with the voice of Mr. Cavalcante’s mother urging him in his native Portuguese to surrender peacefully, the authorities said on Monday.

Lt. Col. George Bivens of the Pennsylvania State Police said at a news conference on Tuesday that one of the sightings of Mr. Cavalcante was probably on Monday evening, when a trail camera picked up a man walking on a property at Longwood Gardens, less than three miles south of the prison.

“He has obtained a backpack, a duffel sling-type pack and a hooded sweatshirt,” Colonel Bivens said.

The Chester County district attorney’s office said on Saturday that a residential surveillance camera had also spotted Mr. Cavalcante near the prison that same day. The office said that the police had also received a report of an attempted burglary at 11:30 p.m. on Friday in the Pocopson Township.

Officials said they believed that Mr. Cavalcante might have been hiding in a heavily wooded area near the prison that is in the vicinity of almost 300 homes.

“We are also asking the community to avoid the wooded area or anything outside of the immediate area around their homes” in the area near the sightings, Colonel Bivens said on Monday.

Because of the sightings, Colonel Bivens said that the Unionville-Chadds Ford School District and the Kennett Consolidated School District, near the area where the sightings have been reported, canceled classes early Tuesday morning.

Local and federal authorities, including the U.S. Marshals Service, announced a $10,000 reward for information leading to the capture of Mr. Cavalcante.

“He’s a bad guy, he needs to be in custody and we’re determined to capture him,’’ Colonel Bivens said.

Deborah Ryan, the Chester County district attorney, said over the weekend that it appeared that Mr. Cavalcante, who officials said is five feet tall and also speaks Spanish, was acting alone.

Mr. Cavalcante was sentenced to life in prison on Aug. 22. Less than a week earlier, a jury had found him guilty of fatally stabbing his ex-girlfriend, Deborah Brandao, Ms. Ryan said in a recent Facebook post. Ms. Brandao had learned of a warrant for Mr. Cavalcante’s arrest in connection with a killing in Brazil, and she threatened to tell the police, according to the district attorney’s office.

After killing Ms. Brandao in April 2021, Mr. Cavalcante, who was living in Royersford, Pa., at the time, tried to make his way back to Brazil but was arrested by the police in Virginia, the district attorney said.