A man who died from a gunshot wound to the leg in south Dublin last Sunday had received an 18-month prison sentence just weeks before his death but avoided serving that time in jail after it was suspended by the judge.On the day the sentence for producing “a large cutting knife” during an assault was imposed, Mark Cullen (39) was released from custody on the condition he kept the peace. Gardaí now believe he immediately came under pressure from men involved in the drugs trade who shot him off Kill Avenue, Dún Laoghaire, resulting in his death last Sunday morning. Though the precise reason he was shot has not yet been confirmed, his death is being linked to the drugs trade.Cullen had gone by arrangement to meet men known to him at Patrician Park at about 8.30am. At least one of the men at the scene was armed with a loaded handgun, which was discharged, wounding Cullen in the leg and resulting in his death at the scene following severe blood loss.Gardaí suspect those behind the shooting did not intend to kill Cullen. Instead, they believe the gun was brought to the location to intimidate him, or possibly to wound him in a punishment attack. Detectives have not ruled out the possibility the gun was fired unintentionally during a struggle at the scene. They also strongly suspected Cullen knew them well, had worked with them in the drugs trade and did not believe they would kill him.Gardaí investigating the killing on Monday arrested a man in his 30s. He is believed to be an associate of the suspected gunman. However, after being questioned about the events of last Sunday morning, he was released without charge.“A file will now be prepared for the Director of Public Prosecutions,” Garda Headquarters said on Wednesday, confirming the man’s release.Cullen, who was a father, had previous addresses in several parts of south Dublin including Shankill, Dún Laoghaire and Ballybrack. He had a large number of previous convictions and had been to prison several times.While he was associated with a family-based crime gang in south Dublin, he was not regarded as a big criminal figure. Many of his previous convictions were for minor offences, often committed after consuming alcohol, such as public disorder and shoplifting. However, he has also produced weapons, including knives, after becoming involved in fights.At his court appearance on June 10th last he was charged with producing a large cutting knife during an incident at a shop in Glenageary, south Dublin, last September. In 2018, he was convicted of producing a telescopic baton as he committed an assault at Shanganagh, Cliffs, Shankill, where he lived for a long period. When that case went to court in 2023 he was given a three-month suspended sentence.At the same 2023 court sitting he received a further two-month sentence for breaching the piece in Monkstown in May 2023, by engaging in threatening and abusive behaviour, with a charge of cannabis possession taken into account.He was jailed for two months last January for a series of shoplifting and handling stolen property offences. He handled a stolen €3,800 e-bike in Ballybrack in May 2025 and stolen items from Centra and Tesco stores.On New Year’s Day 2023, in Ballybrack, he was arrested for being so drunk he was a danger to himself after vandalising a woman relative’s car and breaching the peace.