James Chadwick, 37, died of unexplained injuries in Aberdeen on Wednesday.
Police found his body at his home in the city’s Holland Street after receiving a report in the afternoon expressing concern for a man.
Following the results of a post-mortem examination, the death is being treated as murder.
In a statement released through police, his family said: “The death of James has come as a great shock to our family and everyone who knew him.
“He was a popular guy and would have been well-known around Aberdeen city centre. We would urge anyone who has any information or saw him recently to contact police.
“We would like to thank everyone for their kind messages and we would now ask that we are left alone to grieve in peace.”
Detectives are appealing for information from anyone who may have seen anything unusual around Mr Chadwick’s home. They say there may have been a disturbance eight days before his body was found, between Monday, August 31, and Tuesday, September 1.
Detective Chief Inspector Iain Smith said: “We are aware that a disturbance may have taken place in or around the Holland Street area.
“Door-to-door inquiries have been carried out but I would like to appeal to anyone who may have noticed anything unusual or suspicious in the area around the time mentioned to contact us.
“We would also like to speak to anyone who knew James and may have been in his company during the last week of August or early September.
“We’d like to hear from anyone who may have seen him around this time.”
Police have maintained a heavy presence at the block of flats in the Kittybrewster area where Mr Chadwick’s body was found.
A mobile command unit and several police cars were parked in the quiet street.
Over the weekend, scenes of crime and CID officers took out several bags of potential evidence from one of the apartments.
A police officer also stood guard in the stairwell, blocking access to the upper two floors of the four-storey building.
One neighbour, who did not wish to be named, described Mr Chadwick as a “quiet guy”.