Killers who shot a man outside his Newry home followed their victim in the hours before the murder and fled across the border after the shooting, police have said.
Detectives released new CCTV footage that shows Mark Lovell being stalked by the gang that shot him.
The footage released by police shows Mr Lovell's car travelling through the village around the same time as the gunmen's black C Class Mercedes.
On the first anniversary of the murder, detectives have issued a fresh appeal for help to catch the cross-border criminal gang responsible.
Mr Lovell was shot multiple times at close range by killers who had lain in wait for him at his home at Ardcarn Park, Newry on 1 December, 2022.
Detective Chief Inspector Anthony Kelly said it had been a "planned, ruthless and targeted attack".
He said Mr Lovell had been known to police, but declined to be drawn on a motive.
It has previously been reported that it had been linked to a feud over drugs.
The police said the gunmen's getaway car had been stolen in Dublin in July 2022 and was found burnt out in Dundalk, Co Louth after the shooting.
Police also read out a statement on behalf of Mr Lovell's wife Eileen Hughes.
She said the killing had been brutal and senseless and issued a "heartfelt plea" to anyone with information to help.
Ms Hughes said he is "sorely missed" every day, particularly by his ill mother, for whom he was the sole carer.
She said his devotion of care was "cruelly" used by his killers to target him.
"Mark was an only child. He was his elderly mother's sole carer, and since his murder she has been in hospital broken hearted. She still remains there today.
"Mark was a loving son, daddy, grandaddy and husband. He was a great friend and he is sorely missed each and every day
"We want to take this opportunity to make a heartfelt plea to anyone with information to come forward, to clear their conscience and bring these evil killers to justice, not only for Mark's family and friends but for the good of everyone in the area."
DCI Kelly said the cross-border nature of the crime added complexity and he was working closely with garda colleagues in an attempt to solve it.
He said: "We believe the gunmen lay in wait for Mark before shooting him.
"This was a planned ruthless and targeted attack, one which shocked an entire community and which has left a loving family bereft.
"One life was taken and any passer-by could easily have been injured or killed by the reckless volley of bullets."
A £20,000 reward has been offered by the charity Crimestoppers for information leading to the conviction of those responsible.
