A 45-year-old woman and two men aged 18 and 20 are being questioned by police about the murder of Martin Gavin in north Belfast.
The three people were arrested today on suspicion of murder.
They were being questioned at Musgrave Street police station in Belfast.
Mr Gavin (47) was stabbed at his house on Harcourt Drive on the morning of January 7. He died in hospital four weeks later on February 6.
Last month, independent charity Crimestoppers offered a reward of up to £20,000 for anonymous information it receives that leads to the arrest and conviction of those responsible for the murder.
Detective Chief Inspector John Caldwell made a renewed appeal for information yesterday.
"My team and I continue to appeal to anyone with information to do the right thing and come forward," he said.
"Were you in the Harcourt Drive area in the early hours of Friday 7th January?
"Did you see or hear a disturbance or anyone acting suspiciously?"
Anyone with information, or any dash cam footage, is asked to contact police on 101.
Mr Gavin was the second person to be murdered in Harcourt Drive in the last few months. His house, close to a primary school, is at the upper end of the street.
Mother-of-four Caoimhe Morgan, whose house is at the lower end of Harcourt Drive, was murdered shortly before Christmas.
The 30-year-old was found in her home on December 18.
