Man, 40s, arrested over murder of man in Dún Laoghaire

A man has been arrested in connection with the murder of Mark Cullen in Dún Laoghaire, Dublin, in July.

Mr Cullen, who was 39, was shot dead at Patrician Park on Kill Avenue on Sunday, 5 July.

This morning, gardaí arrested a man in his 40s in connection with the investigation.

He is being detained at a garda station in Dublin.

Mr Cullen, who was from Shanganagh Cliffs, Shankill in Dublin, was shot in the leg and died at the scene.

His was the first gang-related murder this year and the first organised crime gun killing since 2024.

Gardaí previously said they believed that Mr Cullen went to Patrician Park at around 8.30am on 5 July for a prearranged meeting and was fatally injured during a struggle with a handgun or deliberately shot as part of a dispute or so-called punishment shooting.

Mr Cullen was shot in the upper leg and bled to death on the street.

He was known to gardaí for associating with members of a south Dublin drug dealing street gang.

Mr Cullen had convictions for assault, threatening and abusive behaviour, possession of cannabis and carrying a knife.

Detectives were not aware of any danger to his life.

He was last released from prison in May 2025.

Gardaí said their investigations are ongoing.