Four people are now being questioned by police about the discovery of a man’s body in the Creggan Street area of Londonderry in the early hours of Sunday.
On Sunday night, police said they had detained two more people following the earlier arrests of two men aged 26 and 31.
Shortly before midnight on Sunday, the PSNI said they had also detained a man aged 51 and a 35-year-old woman.
Detective Chief Inspector Eamonn Corrigan said: “Shortly before 2.45am this morning (Sunday), police received a report that the body of a young man had been discovered in an alleyway on Creggan Street.
“The man has sustained significant injuries to his head and body and a post mortem examination is due to take place to determine the cause of death.
“I am appealing for anyone who was in the Creggan Street or Little Diamond area of the city late last night (Saturday) or early this morning (Sunday) and who witnessed anything or anyone who has any information that can assist with my investigation to contact detectives on 101 quoting reference 244 of 25/11/18.”
DCI Corrigan added: “Alternatively information can be passed to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”