Detectives are investigating the suspected drug-related deaths of two men over Christmas.
Gardai were called to an address at Rockgrove Terrace in Cork at 1pm on Sunday where a 33-year-old man was pronounced dead.
Seven hours later a second man, aged 32, was removed from the same address and taken to Mercy Hospital in a critical condition.
A Garda spokeswoman said that man died in the early hours of Boxing Day.
Detectives have urged anyone at a gathering at the address over Christmas Eve and Christmas Day to seek medical attention and come forward with information.
Post-mortem examinations on the two men will be carried out at a later date.
Local Councillor Catherine Clancy said there are a lot of rented properties in the inner city area. It is understood the property concerned was divided into flats.
"This is a terrible tragedy for the families of the men especially at this time of the year," she said.
"My sympathy goes to them.
"Everyone has family and these men are somebody's child or brother."