George Gilmore, 44, died after he was attacked while in his car in Carrickfergus on Monday afternoon.
A dispute between loyalist factions in the town has been ongoing for months.
Det Ch Supt Raymond Murray said a link to the south-east Antrim element of the UDA, is a "very strong" line of inquiry.
"At least one of the bullets that was fired at the victim missed and went through the front door of the house and could well have hit an occupant," he said.
He rejected any suggestion that the police have lost any control in dealing with the on-going paramilitary feuds in the County Antrim town, but added: "We need people to come forward and give us evidence."
Det Ch Supt Murray said police believe there were potentially two gunmen involved in Monday's attack.
He said they may have come from an alleyway near Pinewood Avenue in Carrickfergus to carry out the attack, may have made off on foot and may have been wearing dark clothing.
Police have described the murder as a "ruthless attack in broad daylight" and have appealed for help in indentifying those involved.
Det Ch Supt Murray said: "Our thoughts are with the Gilmore family at this time as they come to terms with their loss.
"Those involved had no consideration for the local community when they carried out their attack in a residential street populated with families, young children and older people."
Earlier, Democratic Unionist Party MP Sammy Wilson said the feud involved two factions of the Ulster Defence Association (UDA) paramilitary group.
"One side, in broad daylight and unmasked, have taken the opportunity to try to kill one of the Gilmore family," he added.
Ulster Unionist MLA Roy Beggs urged the factions involved in the feud to remain calm in the wake of the attack.
"Let this be a learning point - stop the paramilitarism, bring it to an end, because it is ruining our communities," the East Antrim representative said.
"I am fearful that others may wish to start a tit-for-tat war, but if that happens everybody loses."
The shooting came after a serious assault on a doorman at a nearby bar on Sunday.
One of the bullets fired during the murder of a high-profile loyalist missed and could have hit someone else, the PSNI has said.