The manhunt for Danelo Cavalcante intensified Sunday when authorities in Pennsylvania announced the escaped killer had been seen hours earlier, had changed his appearance and was driving a stolen van that was later found abandoned.

Cavalcante fled a suburban Philadelphia prison Aug. 31, triggering a massive search that resulted in several sightings. The most recent sightings were in Phoenixville, more than 20 miles northeast of the Longwood Gardens botanical park area where a perimeter had been set up that apparently failed to contain Cavalcante.

"No perimeter is 100% secure, ever" State Police Lt. Col. George Bivens said at a Sunday news briefing. "I'm not going to make an excuse . . . I wish it had not happened."

State police, in a Facebook post early Sunday, said Cavalcante was operating a white 2020 Ford Transit van with a refrigeration unit on top. But Bivens said the van has been discovered abandoned in a field.

Cavalcante had a beard when he escaped Chester County Prison, but Bivens said a video doorbell at the home of a former Cavalcante work associate on Saturday night captured a photo of the fugitive clean shaven and wearing a yellow or green hooded sweatshirt, black baseball style hat, green prison pants, and white shoes.

Authorities say Cavalcante, 34, has little to lose and should be considered extremely dangerous. He faces life in prison after his conviction last month in the murder of his girlfriend. Prosecutors said he stabbed Deborah Brandao, 33, multiple times in front of her 7-year-old daughter and 3-year-old son. Cavalcante fled while being temporarily held at Chester County Prison, about 25 miles west of Philadelphia, pending transfer to a state prison.

Local dairy says its van was stolen by Cavalcante

Police said the keys had been left in the van, allowing Cavalcante to steal it. Baily’s Dairy said in a Facebook post that their delivery van was stolen Saturday night "while we were still here working" and that the dairy was helping with the investigation.

"We are just as disappointed as everyone that he broke through the perimeter in Longwood," the post said. "We appreciate the support of the community and continuing efforts of law enforcement."

Cavalcante crab-walked to freedom

Security footage showed Cavalcante "crab-walking" up a wall before he pushed through razor wire and ran across a roof. The escape took place while his prisoner block was outside in the exercise yard. An officer in a tower who didn't see him slip away has been put on administrative leave, Chester County Prison acting Warden Howard Holland said.

Cavalcante's disappearance was discovered nearly an hour later during an inmate count after the block returned from the yard. Holland said officials determined that the razor wire was insufficient and that planning is underway to better secure the prison with physical barriers and increased staff.

Cavalcante also accused in 2017 murder

Cavalcante, a Brazilian national and former agricultural worker, is also wanted for a 2017 murder of a 20-year-old man over a car repair debt in his native country, the Chester County district attorney's office has said. Investigators learned that Cavalcante fatally stabbed Brandao because she had learned about his open murder warrant in Brazil and had “threatened to expose him to the police,” according to the district attorney's office.