Authorities in Pennsylvania have closed two school districts as a manhunt for a convicted murderer who escaped from prison on 31 August enters its sixth day.

Danelo Cavalcante, 34, was spotted twice overnight on Monday, police said.

The Brazilian national was sentenced to life in prison just last month for stabbing an ex-girlfriend to death.

Officials are also broadcasting messages from his mother pleading for his surrender.

The US Marshals service is offering a $10,000 (£7,955) reward for information leading to his capture.

Police had previously focused their search on a heavily forested area within a two-mile (3.2km) radius of the Chester County Prison in West Chester. By Tuesday, the search area had been expanded after Cavalcante was spotted on surveillance cameras in nearby Longwood Gardens twice on Monday night.

The CCTV images show Cavalcante walking through dense foliage with an over-the-shoulder bag. In some of the footage, he is also seen wearing a dark-hooded sweatshirt.

Robert Clark, the supervisor of the US Marshal task force for eastern Pennsylvania, told CBS, the BBC's US partner, that Cavalante is "desperate and dangerous and probably exhausted".

He is believed to be moving at night and hiding during the day in an area with thick underbrush that officers have sometimes had to hack through by hand. The area also includes numerous possible hiding places - such as sheds - that have complicated the search.

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

Officials are using thermal imaging technology, as well as drones and dogs, in the hunt for Cavalcante. A federal arrest warrant has also been obtained in case he attempts to flee across state lines into Delaware or Maryland.

Two school districts in the expanded search area cancelled classes as a precautionary measure on Tuesday.

On Monday, authorities began using helicopters and patrol cars to blast an audio message recorded by Cavalcante's mother in Brazil in which she calls on him to surrender.

"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," Mr Clark said on Monday. "Perhaps this is what puts him over the edge where we can get a peaceful surrender."

Cavalcante was sentenced to life in prison after being found guilty of stabbing ex-girlfriend Deborah Brandao to death in April 2021 in front of her two small children. He was taken into custody just hours after the murder after fleeing to Virginia.

The Chester County district attorney's office believes that Brandao had "threatened to expose him to the police" after learning that Cavalcante had an open warrant for a 2017 murder that took place in Brazil.

Investigators are still looking into how Cavalcante escaped from the prison and whether he had any help from other suspects. (BBC)

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