Man Arrested in Dún Laoghaire Murder Investigation
A man in his 30s has been arrested in connection with the fatal shooting of 39-year-old Mark Cullen in Dún Laoghaire, County Dublin.
The suspect is being detained at a garda station in Dublin under Section 30 of the Offences Against the State Act, 1939, and can be questioned for up to three days.
Mr Cullen, from Shanganagh Cliffs, Shankill, was shot in the upper leg at Patrician Park, Kill Avenue in Dún Laoghaire yesterday morning and died at the scene from blood loss.
Gardaí believe Mr Cullen went to the location at around 8.30am for a prearranged meeting and was fatally injured during a struggle with a handgun. Detectives are working to establish whether the shooting was deliberate or part of a dispute or so-called punishment attack.
A post-mortem examination is to be carried out today, with detectives awaiting results to determine the bullet trajectory and exact cause of death.
Mr Cullen was known to gardaí for associating with members of a south Dublin drug dealing street gang. He had convictions for assault, threatening and abusive behaviour, possession of cannabis, carrying a knife, and theft. His most recent conviction was last month, when he received an 18-month suspended sentence. He was last released from prison in May 2025.
Detectives had not been aware of any specific danger to his life prior to the shooting.
This marks the first gang-related murder of 2026 and the first organised crime gun killing in Ireland since 2024.
A murder investigation is now underway. Gardaí are appealing for any witnesses, or road users who were travelling near Kill Avenue between 8am and 9am yesterday and may have camera footage including dashcam, to contact Dún Laoghaire Garda Station on 01 666 5000, the Garda Confidential Line on 1800 666 111, or any garda station.
LTT Media — 6 July 2026