Detectives hunting double murder suspect James Allen have urged Yorkshire residents to lock their doors and windows after reported sightings of him on the East Coast raised fears the killer could strike again. Allen, a 35-year-old drug user with previous convictions for violence, is believed to have killed his former next-door neighbour in Middlesbrough and murdered a Whitby housewife while on bail for other offences. Police called on him to hand himself in yesterday as they revealed sightings of the suspect had been reported in Whitby, Scarborough and Middlesbrough. More than 100 officers from the Cleveland and North Yorkshire forces are investigating the murders of Colin Dunford, 81, and Julie Davison, 50. Both victims suffered head injuries. The detective leading the inquiry, Temporary Detective Chief Superintendent Gordon Lang of Cleveland Police, said it was a “24/7 operation” that would not stop until Allen is found.