A man aged 27 has been arrested on suspicion of murder after three bodies were found in Exeter.
An 80 year old was found on Monday in Bonhay Road, two others aged 84 at an address in Cowick Lane on Tuesday.
Officers believe the incidents are linked and investigations continue.
Superintendent Matt Lawler, the 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.
"Residents in the area of both Bonhay Road and Cowick Lane will continue to see police cordons today as we continue vital work.
"The local neighbourhood team will be out on foot over the next few days in order to provide advice, support, and to answer questions.
"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.”
"Anyone who was in the area of Bonhay road and Cowick Lane between 8am on Sunday 10 February and 1pm on Tuesday 12 February and may have seen anything relevant to get in touch with police.
"Anyone with information is asked to contact police on 101 quoting log 472 11 February. "