(NewsNation) — Police in Pennsylvania warned residents Monday night that escaped murderer Danelo Cavalcante is “possibly armed” and urged them to keep their vehicles and homes locked as the search continued for a 12th day.

The warning came via an emergency phone alert sent to those in Chester County, where Cavalcante is believed to be hiding. Searchers say Cavalcante, who broke out of a county jail nearly two weeks ago, has changed his appearance, stolen a vehicle and tried to contact acquaintances.

Police converged on an area Monday night in South Coventry Township where there was a possible sighting of Cavalcante. K-9s and a helicopter were deployed to aid in the search.

Sources confirmed to NewsNation that a homeowner in the area shot at Cavalcante, but he was able to steal a rifle from there first.

Police have expanded their search area after Cavalcante slipped through the initial perimeter.

Earlier Monday, Lt. Col. George Bivens of the Pennsylvania State Police said at a news conference that police are no longer using a containment model to find Cavalcante, but are instead putting into place a “variety of investigative resources.”

“We continue to receive tips and information from the public and are following up on those,” Bivens said.

At the news conference, police said they increased the reward for information leading to Cavalcante’s capture to $25,000.

Cavalcante’s sister, meanwhile, is facing deportation as she is in an overstay status, Bivens said. She is currently in ICE custody, Bivens added.

Police say Cavalcante tried to contact two acquaintances to aid in his escape. These people had not had contact with Cavalcante for years, Bivens said, and had been prior work associates, not friends, of the escapee. Since then, police said, there have been no other credible sightings of Cavalcante.

Shortly before 10 p.m. Saturday, he went to an East Pikeland Township home of a person he had worked with several years ago and asked to meet with him, police said. The homeowner, who was at dinner with his family and didn’t respond, called police after returning home and reviewing his doorbell video.

Shortly after 10 p.m. Saturday, police said, Cavalcante went to the Phoenixville area home of another former work associate. This former associate also wasn’t home, police said.

NewsNation correspondent Evan Lambert spoke to family of the people at a home Cavalcante visited Saturday night, who said they immediately called 911 when the escapee asked for help.

“My family is afraid,” the person told Lambert.

They say they do not support what Cavalcante is doing and want him held accountable.

Cavalcante was seen on doorbell video images with a cleanshaven face and wearing a yellow or green hooded sweatshirt, black baseball cap, green prison pants and white shoes, police said. He was driving a 2020 White Ford Transit van that has a refrigeration unit on the top and had been reported stolen by Baily’s Dairy.

Baily’s Dairy said on its Facebook page that the delivery van was stolen between 7 p.m. and 10 p.m. Saturday “while we were still here working.”

Cavalcante later abandoned the vehicle, Bivens said, with police believing he did so at least in part because it was low on fuel. While law enforcement was searching the immediate area for any signs of him, authorities were concerned that he would attempt to obtain another vehicle or had already done so.

The theft wasn’t noticed for hours, and in the meantime, Cavalcante traveled more than 20 miles northeast to East Pikeland Township and Phoenixville.

The public can expect to see a “significant ” law enforcement presence around East Nantmeal Township where the van was recovered, Bivens said Monday, along with other areas of northern Chester County.

Some schools in the region planned to hold outdoor activities inside. Owen J. Roberts School District in Pottstown announced that there would also be an increased security presence at its schools Monday, including local law enforcement officers.

Cavalcante escaped from the Chester County Prison while awaiting transfer to state prison on Aug. 31 after being sentenced to life for fatally stabbing his ex-girlfriend in 2021. Prosecutors say he wanted to stop her from telling police that he was wanted in a killing in his home country of Brazil.

Police on Saturday had reported two more confirmed sightings of Cavalcante within the search area around the Longwood Gardens botanical park, the center of the search in recent days. Bivens said Friday that about 400 personnel were taking part in the search, including tactical teams, tracking dogs, and officers on horseback as well as aircraft.

Despite the massive searches, Bivens said the area had some underground tunnels and “very large drainage ditches” that were impossible to secure completely. Police had been planning to use close to 600 personnel Monday for “one massive sweep” of the search area, he said.

Authorities on Friday announced the firing of the prison tower guard on duty when Cavalcante scaled a wall by “crab-walking” up from the recreation yard, climbed over razor wire, ran across a roof and jumped to the ground. His escape went undetected for more than an hour until guards took a headcount.

The Associated Press contributed to this report.