The body of Anthony Lewis was found some time after his death
The death of a man, 52, is under investigation by the police watchdog after it is thought the last people to see him alive were two officers.
Anthony Lewis's body was found in his home in Maindee, Newport on Tuesday. He had been dead for some time.
The two officers who took Mr Lewis, who was deaf, into his home may have been the last people to see him alive.
Gwent Police referred the matter to the IPCC as a potential death following police contact.
As well as being deaf, it is also understood Mr Lewis had speech difficulties and relied on lip-reading and sign language to communicate.
A post-mortem examination has not been able to establish what he died from.
The IPCC said members of the public had reported seeing Mr Lewis on 20 October, at some time between 1130 BST and 1300 BST, in Wharf Road in the city with the two officers.
It is understood that these officers went to Mr Lewis' assistance and helped him home and into his house in Rudry Street, the IPCC said.
Another man, who is believed to be a council worker, was also assisting Mr Lewis in Wharf Road before the police arrived and investigators also want to speak to him.
IPCC Commissioner for Wales Tom Davies appealed for anyone who could help to come forward.
He said: "Mr Lewis was found some time after his death and this must have been very distressing to his family and friends.
"I would like to offer them my condolences at this difficult time for them.
"You may be a neighbour, or might have seen Mr Lewis out shopping, or in a local pub or club."
He added: "I would urge anybody who knows anything, no matter how small or seemingly trivial, to come forward and contact the IPCC."
Anyone who saw Mr Lewis with two officers in Wharf Road or Rudry Street, or who had contact with him on October 19 or 20, is asked to contact the IPCC on 0800 096 9076.