The man shot dead in front of his son in a supermarket car park in Bangor, Co Down on Sunday has been named locally as Colin Horner.
The 35-year-old victim, who was shot a number of times in the Sainsbury's car park at Balloo Link in Bangor, was a friend of leading loyalist Geordie Gilmore.
Gilmore was shot dead in a paramilitary feud in March.
It is believed that Mr Horner was approached by a gunman in the car park who shot him up to six times.
The murder is being linked to a long-running feud between two different factions of the Ulster Defence Association (UDA), with much of the violence centred on Carrickfergus in Co Antrim.
One of the factions was led by Gilmore.
Mr Horner was a loyalist associate of Gilmore’s and acted as one of the pall-bearers at his funeral.
One well-placed source said Mr Horner, fearing for his safety after the Gilmore murder, moved to Bangor to try to “take himself away from the feud”.
Sources say the feud relates to a turf war over drugs and other forms of criminalit. The Gilmore group was also accused of removing guns from the other UDA faction.
‘Completely reckless act’
Detective Supt Richard Campbell, who is leading the murder inquiry, said on Monday that Mr Horner had just put his three-year-old son into the back seat of his black Nissan Pulsar car when the gunman approached.
He said the killer’s head was covered in a black hoodie and he also appeared to be wearing a face mask.
He said he fired a number of shots from a handgun at his victim and one of the “stray” bullets hit another car. “It was a completely reckless act,” Det Supt Campbell said.
Mr Horner was taken to hospital but died from his injuries shortly after admission.
“His three-year old son was in the car and was immediately beside his father when he was shot dead. It’s a hugely barbaric act and something that will undoubtedly live with this young boy for the rest of his life,” said Det Supt Campbell.
The officer said that at least one accomplice drove the gunman from the scene in a red Ford Mondeo with false number plates. The car was found burnt out between Bangor and Newtownards. It was believed another accomplice or accomplices picked them up at that scene.
“Mr Horner was known to the police but that does not take away from the fact that this was a man with a three-year old son who was brutally gunned down in a car park full of people on a busy Sunday afternoon in Bangor,” said Det Supt Campbell.
He said that his team of officers was examining CCTV from the car park and also appealed for witnesses to come forward, particularly those who might have mobile phone or car dash-cam footage of the scene of the shooting or of the getaway car.
Police in Carrickfergus have been trying to keep the disputing sides apart for the past two years. Tensions have been particularly high in the Castlemara estate in Carrickfergus where a number or serious disturbances have occurred, sometimes involving more than 100 loyalists.
Numerous people have been arrested over the past two years. On at least one occasion a loyalist suspect waived away his opportunity to be released on bail, reckoning that it was safer to be in prison.
In July last year, the North’s Policing Board was told that the PSNI had spent £1.6 million policing the Carrickfergus dispute.
At the time Assistant Chief Constable Stephen Martin told the board he was concerned that if the dispute was not brought to an end, someone was going to “end up hurt or dead”.
Superintendent Brian Kee, District Commander Ards and North Down District, described Mr Horner's 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. We are very lucky that we are not also dealing with the death of this child,” he add.