Police issued a tearful message from the mother of a man wanted in connection with two double killings in North Yorkshire.

Detectives are hunting Mark Hobson in connection with the murders of twin sisters Claire and Diane Sanderson and an elderly couple at the weekend.

In the message, his mother Sandra Hobson, pleads with him to contact family or police.

She says: "Please don't hurt anyone -there are people who can help you."

The tape was played at a press conference held by North Yorkshire Police - who also said the two murder scenes, which are 25 miles apart, were now being positively linked.

Former bin man Mr Hobson, 34, is being sought following the deaths of the 27-year-old twin sisters at their flat at Camblesforth near Selby. They were found dead on Sunday.

Claire was Mr Hobson's girlfriend and he had lived with her at the flat for three months.

Det Supt Javad Ali said Diane was alive on Saturday as she was seen and spoken to by a relative.

"Forensic tests showed Claire died a number of days ago. We are trying to establish exactly when she died," he said.

Deputy Chief Constable Roger Baker said he could now confirm the murders were linked.

"I can now tell you that from evidence provided at the scenes of the crimes we can positively link the murder sites," he said.

Two women arrested by police, over circumstances relating to a crime scene, have now been released on police bail.

Police also want to quiz Mr Hobson about the deaths of James Britton, 80, and his 82-year-old wife Joan, found dead 25 miles away at their home in Strensall.

Cars belonging to Mark Hobson and Diane Sanderson had been found near Camblesforth, police revealed.

They also said they did not believe Mr Hobson had any form of vehicle or transport.

Mr Baker said: "We are utilising every resource to bring the person or persons responsible to justice.

"We are working tirelessly towards this."

He also re-inforced a warning for the public not to approach Mr Hobson.

"This man is hiding somewhere but should not be approached under any circumstances," he said.

Different weapons had been found at the two murder scenes and the probable murder weapon for the Camblesforth killings had been discovered, police said.

Detectives said Diane had been strangled after visiting her sister, who had suffered from a "violent assault".

The bodies of the Brittons were found in their house by a neighbour several hours after the twins were discovered.

Former RAF flight sergeant Mr Britton had died from stab wounds and his wife, who could only walk with a frame, had been the subject of a "vicious assault including stab wounds".

The couple's daughter, Catherine Wilkins, issued a statement through police saying her family had been left "very shocked and distressed" by their deaths.