Police in the North are trying to recover the gun used to kill a 36-year-old Dublin man in Belfast on Saturday morning.
Robbie Lawlor from Donaghmede was shot dead outside a house in the Ardoyne area of the city.
He was a suspect in the murder of Drogheda teenager Keane Mulready-Woods, the 17-year-old who was abducted and killed earlier this year.
Three men and a teenager were arrested in connection with Saturday’s murder; however, one of the men has since been released without charge.

PSNI Detective Superintendent Jason Murphy said police have spoken to Mr Lawlor’s family.
“Understandably, they are distraught at what has taken place and they are dreading the thought of what tomorrow may bring for them,” he said.
He said investigators don’t believe he was in Belfast by accident.
“My belief at this stage is that he had some reason to be there but a key line of enquiry for me and my team is to establish what that reason was,” he said.
“At this stage, I believe that a single gunman was involved. I believe multiple shots were fired and the gun has not yet been recovered.”
He said the “brutal killing” put children and other members of the Ardoyne community at risk.
Police have carried out searches in Crumlin and west Belfast as part of the investigation.