Three elderly men who were murdered in their own homes just a mile apart all suffered serious head injuries, police have revealed.
The bodies of twins Dick and Roger Carter, 84, and Anthony Payne, 80, were found less than 24 hours apart in Exeter, Devon.
The ambulance service alerted police to Mr Payne’s body at his terrace house in Bonhay Road at about 3pm on February 11.
And at 1pm the following day, officers went to the Carter brothers’ detached home in Cowick Lane after their bodies had been found.
The deaths have been linked due to the age of the three victims, the presentation of the properties and the injuries they all sustained.
Police would not say whether any weapons had been used during the violent attacks but dismissed reports that firearms were involved.
A 27-year-old man arrested on Tuesday evening remains in custody at Heavitree police station in Exeter.
Devon and Cornwall detectives have yet to interview him in connection with the deaths and have been granted a further warrant of detention for 36 hours by magistrates.
The man can be held for a total of 96 hours before he is released or charged.
Detective Chief Inspector Roy Linden, deputy head of major crime, said: “The investigation into these three incidents remain connected.
“Due to the serious head injuries sustained by all three victims and the presentation of the properties and the age of the victims, we are treating this as a single multiple murder investigation.
“Following the post-mortems, which were completed yesterday, is has been confirmed that all three victims sustained serious head injuries.”
Mr Linden said detectives had over 150 “priority lines of inquiry” and had seized nearly 300 exhibits.
He said officers were yet to interview the suspect and that was one of the reasons they had sought a warrant of further detention.
“There are various issues but we were certainly ready to interview but there are other issues as well so we could not speak to him,” he said.
“You would expect us to be looking at the detailed background of all the parties involved.
“What we can say is that there was no clear motive at this time across the investigation and no clear relationship.”
The detective said the information the investigation had uncovered so far supported the view that the three murders were linked.
“There are other factors which I can’t go into for operational reasons but our investigation as it has progressed over the last 24 to 36 hours has reaffirmed the investigations are linked,” he added.
Police have also visited nine addresses to “confirm the safety of occupants” and urged anyone in the area of Bonhay Road and Cowick Lane between 8am on February 10 and 1pm on February 12 to come forward.
Superintendent Matt Lawler, local policing commander for Exeter, East and Mid Devon, said: “Firstly, on behalf of the family I would like to appeal for everyone to please continue to avoid speculation.
“Family members of the elderly gentlemen have specifically asked for privacy whilst they come to terms with the enormity of what has happened to their loved ones, and whilst of course we understand the public interest, I am sure we would all wish to respect that.
“We would therefore ask that everyone gives the family some time and space whilst they are being supported by specialist family liaison officers.”
Floral tributes continued to be left outside the home of the Carter brothers, who had previously run an agricultural business and a greengrocers.