Murder suspect James Allen knew one of his alleged victims, police have said.
Cleveland Police said Allen lived next door to Colin Dunford in Middlesbrough. The 35-year-old suspect is being urgently sought by police following the separate murders of Julie Davison, 50, in Whitby, North Yorkshire, and 81-year-old Mr Dunford.
At a press conference Chief Superintendent Gordon Lang confirmed Allen was on court bail for an offence which was not disclosed. He confirmed Allen had also had contact with the probation services and was being investigated for other alleged offences which he would also not disclose. He said Allen had previous convictions for violence and was a known drug user.
The detective said there had been a number of reported sightings in Middlesbrough, Scarborough and Whitby. He also urged the suspect to give himself up, saying: "James Allen stop now. Do the right thing. Consider the consequences. You have inflicted terrible injuries and death on two families. Stop and hand yourself in."
Mr Lang said: "People should take common sense precautions, safety first. Lock their doors, lock their windows and check who's knocking on your door. Clearly this is a man who is a dangerous man but we are putting absolutely everything into finding him, tracking him down and bringing him to justice.
"There's a massive police operation in place here. Over 100 detectives, two forces, not an inch between these two forces, absolutely working in partnership with one goal and that is to find James Allen and arrest him.
"I would appeal to general members of the public. If you've got an elderly neighbour then look out for them, reassure them. Be public spirited, be community spirited and help them."
Cleveland Police earlier confirmed a number of officers were involved in an "ongoing operation" on a housing estate in the Pallister Park area of Middlesbrough as part of the huge effort to find Allen. Police stood guard outside a property in Lothian Road in Middlesbrough as forensic officers in white boiler suits entered the property. Neighbours said Allen was seen at the property at the weekend.
The detective said he was also investigating an alleged offence at Allen's address in Lothian Road over the weekend, but officers had not been able to speak to him about it.
Mr Lang said Allen, who was originally from Blackpool, knew Mr Dunford when he lived next door to him in Leven Street about a year ago. The officer said it was not thought Allen knew Ms Davison. He said robbery was a possible motive behind the attacks, but he stressed he was keeping an "open mind" and was focusing on apprehending Allen as soon as possible.