An escaped murderer's mother joined police efforts to find him, days after the 34-year-old man vanished from a Pennsylvania prison. But a growing manhunt is continuing as the woman's son has not yet heeded her calls to surrender.

Danelo Cavalcante escaped from Chester County Prison in West Chester, about an hour's drive from Philadelphia, around 8:45 a.m. Thursday. He had still not been captured as of Tuesday afternoon. 

"He is desperate and dangerous and probably exhausted," Deputy U.S. Marshal Robert Clark, the supervisor of the U.S. Marshal fugitive task force for eastern Pennsylvania, told CBS News.

Earlier this week, authorities broadcasted a message from Cavalcante's mother in the search area.

"That was broadcast through the helicopter yesterday and through the patrol cars in the hopes that perhaps, as desperate as he is, maybe he has a change of thought and hears his mother telling him to surrender and his family cares about him," Clark said on Monday. "He's desperate, he's hungry, he's been in the woods, he's dirty, perhaps this is what puts him over the edge so that we can get a peaceful surrender."

Cavalcante is a Brazilian national fluent in Portuguese and Spanish. Cavalcante also speaks some English, authorities said. His mother, who is in Brazil, recorded the message for him in Portuguese.

Cavalcante was last seen on Monday evening, said Pennsylvania State Police Lt. Colonel George Bivens at a news conference early Tuesday. Officials previously said there had been four confirmed sightings of Cavalcante in a 2-mile radius in the days since his escape. The focus of the search has been in the area around Pocopson Township, which located within Chester County. 

The most recent sighting happened within the perimeter of the original search area, Bivens said, but authorities have since shifted those boundaries slightly because security footage provided by a nearby botanical garden appeared to capture Cavalcante on their property.

On 09/04/2023 at 8:21PM and 9:33PM, Escaped murderer Danelo Cavalcante was seen on a trail camera at Longwood Gardens in East Marlborough Township, Chester County. Anyone with information is asked to contact the tip line at 717-562-2987. pic.twitter.com/bSPWBxuTRB

— Trooper Grothey (@PSPTroopJPIO) September 5, 2023

"We had one additional sighting of Cavalcante last evening within that perimeter and conducted a multiple hours long search of the area, but were unable to locate him," Bivens said at Tuesday's briefing. "Early this morning, we were notified by security at Longwood Gardens that they had trail camera photos taken on their property which appear to be Cavalcante. This area is just south of the perimeter."

Investigators confirmed the person seen in those images was Cavalcante, who had not changed his appearance but was seen wearing a hooded sweatshirt and carrying items he did not have before, including a backpack and a duffel bag. The Pennsylvania State Police tweeted the images on Tuesday.

The Unionville-Chadds Ford School District and the Kennett Consolidated School District closed their schools and offices Tuesday as the search for Cavalcante continued. Bivens said law enforcement would work with the districts "to determine what will occur in coming days."

Clark said Cavalcante is moving at night and hiding during the day, telling CBS News on Tuesday that the landscape has posed challenges for law enforcement trying to capture him. There are large patches of wooded areas with thick underbrush that officers are forced to hack through at times, as well as numerous structures such as sheds to search, Clark said.

"We are trying to stress him out, keep him on the move, squeeze him, " Clark said. "This is what we do. His desperation will not outlast our dedication."

Authorities are asking people in and around the search area to secure their homes, vehicles, businesses and any outbuildings. They believe the items Cavalcante obtained since his escape were stolen from a car or home, Clark told CBS News.

"Cavalcante has clearly already obtained some clothing and unknown other supplies, and we want to minimize any opportunity to obtain anything more," Bivens said Tuesday, requesting that anyone with security cameras on their properties scan the footage and report anything suspicious to the state police. He noted that additional law enforcement agents from the FBI and U.S. Customs and Border Patrol have been mobilized to join the manhunt.

More than 250 officers from multiple agencies are now assisting the search, including 40 members of the U.S. Marshal Service fugitive task force, with investigators using thermal imaging, night goggles, drones, helicopters, dogs and other technology in the manhunt. 

Bivens said Tuesday that authorities have received more than 100 tips relating to Cavalcante and are following up on all of them. A federal warrant has also been obtained to authorize the escapee's arrest if he flees Pennsylvania to Delaware or Maryland nearby.

"When you talk a 2-mile radius, you've got to remember this is a 5-foot tall gentleman, 120 pounds, and this is a heavily, heavily wooded area," Clark said. "It's very, very thick back there. There's a lot of ravines. There's a lot of hiding spots."

At a news conference Monday, Bivens described what was at the time the most recent sighting of Cavalcante, which happened on Sunday afternoon.

"It was a trooper, actually, that observed him at some distance, gave chase, but was unable because of the terrain and some other obstacles there, was unable to get to him before he disappeared," Bivens said. 

Officers have investigated two burglaries while searching for Cavalcante. They've asked that people in the community check on their neighbors, while Bivens warned at Monday's briefing of the possibility Cavalcante would try to obtain food, clothing and shelter on the run.

"He is going to be looking for a means to sustain himself," Bivens said. "He's going to need clothing. He's going to need food and just to get in out of the weather. It's pretty hot out there."

Cavalcante was convicted of first-degree murder on Aug. 16 for fatally stabbing his 33-year-old former girlfriend in April 2021. Her family has been notified of Cavalcante's escape, authorities said. Cavalcante was sentenced to life in prison. He's also wanted in connection with a homicide in Brazil. 

Authorities stressed that people should not approach Cavalcante if they see him. Anyone who spots him or has information should call 911. The Marshals Service and the Chester County District Attorney's Office are offering a combined $10,000 reward for information leading to an arrest.

Officials have not shared details on how Cavalcante escaped, saying it's under investigation.

"The prison is very aware of whatever vulnerabilities they have and they have made efforts to correct those vulnerabilities," Chester County District Attorney Deb Ryan said.

CBS News senior investigative reporter Pat Milton contributed to this report.

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• Pennsylvania

Aliza Chasan

Aliza Chasan is a digital producer at 60 Minutes and CBS News.

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