"Violent criminal" found dead in police custody was chief suspect in recent knife attack

Lee McDonnell, 34, was found unresponsive in a Dublin Garda [police] station cell on Saturday.

Despite best efforts from members of An Garda Síochána, the Ballyfermot native was later pronounced dead.

The Dublin criminal is understood to have been arrested on Saturday on foot of outstanding warrants and taken into garda custody.

Robin Schiller of the Irish Independent spoke on Newstalk Breakfast on Monday morning, detailing McDonnell’s lengthy criminal history.

"His most recent run-in with the law, Gardaí believe, came last weekend,’ Mr Schiller explained.

"Thomas Griffin, a 31-year-old man from Ballyfermot, was attacked near the Wat Memorial Garda Island Bridge.

"He attempted to flee for his life, swimming across the River Liffey to the Chapelizod Roadside. Unfortunately, he was found unresponsive there and died a short time later."

Thomas Griffin.

The journalist detailed that it was believed McDonnell had "slashed" Griffin before he entered the river.

McDonnell’s coloured past featured more than 130 convictions for a range of offenses, including aggravated burglary, robbery, and machete attacks.

Mr Schiller told of how Mr McDonnell’s death is understood to have been as a result of ingesting a "large quantity of drugs in order to secrete them."

Garda watchdog, Fiosrú, have since launched an investigation following a referral by a Garda Superintendent.

A statement from the organization said: "Fiosrú, Office of the Police Ombudsman, received a referral from An Garda Síochána on Saturday, June 6 2026. The referral was made by a Garda Superintendent under section 203(1) of the Policing, Security and Community Safety Act 2024.

 "The referral was made following the death of an individual in the Dublin Metropolitan Region. Fiosrú’s on call team of investigators have attended the scene.

"As the matter is now under investigation, pursuant to section 208(1)(b) of the Policing, Security and Community Safety Act 2024, Fiosrú cannot make any further comment."

* This article was originally published on Extra.ie.