A loyalist shot dead in front of his young son in a supermarket car park had recently relocated to the area amid concerns he would be targeted in a paramilitary feud.
Colin Horner, from Carrickfergus, Co Antrim, was gunned down by a lone gunman among crowds of shoppers outside the Sainsbury's superstore on the outskirts of Bangor, Co Down.
Mr Horner, 35, was an associate of fellow Carrickfergus loyalist George Gilmore, who was shot dead in the town in March.
The 44-year-old was killed as part of a long-running feud among rival loyalists in Carrickfergus.
Facing similar threats to his life, it is understood Mr Horner relocated from Carrickfergus to Bangor
Mr Horner's young son witnessed his father's murder on Sunday afternoon.
The Police Service of Northern Ireland said it was lucky the youngster was not killed or seriously injured as well.
There were reports of a confrontation before the killer fired four to six bullets at his victim.
The victim was targeted next to a black SUV type vehicle on the edge of the supermarket car park and detectives believe that there may have been more than 100 witnesses to the shooting and the aftermath.
PSNI Superintendent Brian Kee described the murder as brutal, senseless and horrendous and warned of the psychological trauma the man's son has suffered.
"This cold blooded murder was carried out in broad daylight in front of families who were out enjoying this Bank Holiday weekend," he said.
"The recklessness of this murder is all too evident.
"It is beyond belief that the gunman shot the victim when he was out with his son.
"This young boy witnessed everything and he will undoubtedly carry that memory for the rest of his life."