Police have confirmed they informed the son of murdered Coleraine man Kevin McDaid that he is under threat from loyalists.
PSNI officers visited the McDaid home late on Tuesday night and told Ryan McDaid they had information that he was under threat.
The warning comes as the Parade Commission meets to review its decision over a Pride of the Bann parade which is due to be held in the town on Friday night.
The security minister Paul Goggins has appealed for calm ahead of the potential parade.
Coleraine councillor Billy Leonard said the threat to the dead man's son was the ultimate insult.
"These sectarian loyalists have murdered Kevin, badly beaten his wife Evelyn and now deliver the ultimate insult by threatening one of the sons," he said.
"This family have suffered enough: they must be able to grieve without further pressure. Those loyalists responsible must now publicly withdraw the threat and close down forever and the Police need to confirm which loyalist group the threat emanates from."
Another man was arrested on Wednesday for questioning about the murder of Mr McDaid.
The 33-year-old was detained in Coleraine and taken to the Serious Crime Suite in Antrim.
Ten people are now in custody in connection with the killing, after a man was released without charge on Wednesday afternoon.
Two other men arrested in connection with the killing were released without charge on Tuesday night.
The 49-year-old father of four was beaten to death by a loyalist mob yards from his home on Sunday night after Rangers claimed the Scottish premier league title.
A second man, Damien Fleming, 46, is fighting for his life in hospital after being assaulted during the same disturbances.
The independent Police Ombudsman has been called in to investigate claims that the police did not do enough to prevent the violence.
© Press Association