Greater Manchester Police said the 63-year-old woman sparked an investigation at a house on Matlock Road in Reddish, near Stockport, after walking into a police station and telling officers she had killed a man “a number of years ago”.
Investigators searching the property on Tuesday discovered human remains, which are believed to be those of a man.
Door-to-door inquiries have been conducted on the street, with residents being asked if they know a man called Kenneth Coombes.
The questionnaire suggests Mr Coombes was in his late 80s in 2005.
A man by the same name who was recorded as living on the street would have been 99 years old today.
The man was registered as living with a 63-year-old woman called Barbara Coombes.
Police have not released the identity of the woman held in custody after she made the claim at Cheadle Heath Police Station on Sunday.
Neighbours described their shock at the body’s discovery, with one telling the Daily Mirror: “I cannot believe it.”
Detective Inspector Dan Clegg, of GMP’s major incident team, said following a search of the garden, officers discovered remains which were later confirmed to be human by a forensic pathologist.
“The investigation is still in its early stages and many questions still need answers,” he added.
“We will continue our work at the scene through the night and hope in the coming days we can piece together the exact circumstances surrounding the man’s death.
“I would like to thank the community for their support as we continue to carry out our enquiries and we would like to reassure them that this is being treated incredibly seriously and we will do all that we can to find out what happened.”
The man is yet to be formally identified and a Home Office post-mortem is due to take place in the next 24 hours.
GMP said that the man’s family, who are being supported by specially trained officers, have been informed.