A man found dead at his flat in Shrewsbury suffered head injuries, police said.
The body of Wesley Morris, 30, was discovered at his home in Lancaster Road on Tuesday.
A 39-year-old man arrested in the town on the same afternoon is being held by officers on suspicion of murder.
A post-mortem examination by a Home Office pathologist has established the cause of Mr Morris's death as severe head injuries.
Investigations are ongoing at the scene in Lancaster Road and at several other addresses in Shrewsbury. More than 30 detectives and uniformed officers are still involved in the investigation.
The 39-year-old man remains in custody, after Shrewsbury magistrates granted police a further extension to hold him, the West Mercia force said.
The body of Mr Morris was discovered shortly before 1345 BST.
Det Supt Paul Williamson, of West Mercia Police, said: "We have nearly completed our work at some locations, but are likely to continue examinations at the scene for at least several more days.
"I appreciate it has been a difficult time for the local community, especially for family and friends of Mr Morris."