Police investigating the death of Donald Fraser-Rennie in Ballymena have been granted an additional 36 hours to question two men.
The 33-year-old's body was discovered at a flat in Crebilly Road on Wednesday morning.
Two men aged 29 and 33 were arrested on suspicion of murder on Wednesday.
Police said Mr Fraser-Rennie was the victim of a "vicious, sustained and violent" beating.
Officers from the major investigation team said his body was found at a flat in Crebilly Road in the Ballykeel estate.
PSNI Det Ch Insp John Caldwell Detective Chief Inspector John Caldwell appealed to anyone with information to contact detectives.
"I am also keen to speak to anyone who had been in contact with Donald at any time between Tuesday 29 September and 01:00 BST on Wednesday 30 September and anyone who was in the Crebilly Road between mid-day on Tuesday and 01:00 BST on Wednesday," he said.