A 27-year-old man has been arrested on suspicion of murder after the bodies of three men in their 80s were found in two properties in Exeter, Devon and Cornwall Police said.
The deaths of the three men, one aged 80 and two aged 84, are being treated as suspicious and are being formally linked, the force spokesman said.
The body of an 80-year-old man was found at an address in Bonhay Road at around 3pm on Monday and the bodies of the two 84-year-olds were found after officers were called to a property in Cowick Lane at 1pm on Tuesday.
Police arrested the 27-year-old man the same day and he remains in police custody.
Superintendent Matt Lawler, the force’s local policing commander for Exeter, East and Mid Devon, said: “I know that this news will cause significant and understandable concern and is an unprecedented event in our city which has shocked us all.
“I know that everyone’s immediate thoughts will be with the family and friends of these gentlemen, and as you would expect, we are providing as much support as we can to them.
“The investigation is being led by our major crime investigation team, supported by local detectives, forensic staff, family liaison officers, and an extensive range of other specialists who have been working around the clock since Monday afternoon.”
Lawler said residents in Bonhay Road and Cowick Lane would continue to see police cordons on Wednesday as officers continued their enquiries.
“The local neighbourhood team will be out on foot over the next few days in order to provide advice, support, and to answer questions,” he added.
“While a man has been arrested on suspicion of murder in relation to these incidents, we must keep an open mind and avoid speculation as we are still in the very early stages of what is already a complex investigation.
“We have therefore issued an appeal for information from the public and for any potential witnesses who were in either area during specific times. It is vital that anyone who has any information shares with us it as soon as possible.”