Fresh sightings of a violent convicted criminal suspected of killing two people in their own homes have prompted police to widen the focus of a huge manhunt.

James Allen, 35, was last seen in Leeds on Friday afternoon, West Yorkshire Police said, but he was also spotted in the city in the early hours of Friday morning.

An urgent appeal to find Allen was issued by Cleveland Police and North Yorkshire Police following the murders of Julie Davison, 50, in Whitby, North Yorkshire, and 81-year-old Colin Dunford in Middlesbrough.

West Yorkshire Police joined the manhunt after Allen was seen on CCTV footage walking along Harehills Lane at 4.41pm on Friday. A spokesman said: "Investigations continue to be focused upon the Leeds area and officers are liaising closely with colleagues in Cleveland." He added: "Mr Allen is considered dangerous and we would ask members of the public not to approach him but to contact us immediately."

Cleveland Police also confirmed another sighting of Allen in Leeds shortly before 3am on Friday. A force spokeswoman said it was possible Allen was now in a different location but she urged anyone who saw him to call 999.

Inquiries are still being carried out in Middlesbrough and North Yorkshire, with more than 100 detectives working on the case.

Police also released CCTV images of Allen in Scarborough earlier this week. The pictures showed Allen in a cash exchange in the seaside town on Tuesday and Wednesday and in a sports shop on Wednesday.

Temporary Detective Chief Superintendent Gordon Lang said the images showed Allen could be trying to change his appearance by growing his hair. The detective told a news conference in Middlesbrough: "The photographs will show James Allen throughout the course of the week, caught on camera, and show signs of hair growing through at both sides of his head. He was described as bald but there's now clear signs of hair growing."

Mr Lang confirmed Allen stayed in a bed and breakfast, thought to be the Allerton Croft Hotel, in Scarborough on Wednesday night.

The detective said Cleveland Police had received hundreds of calls in response to appeals and urged anyone with information or anyone sheltering Allen to contact them.