A man remains in a critical condition in hospital today after being stabbed 13 times in Co Donegal yesterday morning.
The 28-year-old victim is believed to be the son of Frank Shortt, who spent three years in prison in 1995 after being wrongly convicted of allowing drugs to be sold in his Inishowen nightclub.
Gardai arrested a man at the scene of the stabbing in Letterkenny yesterday, but he has since been released without charge.
However, a second man was detained in Monaghan in the early hours of this morning.
The victim sustained two punctured lungs, as well as wounds to his chest, head and neck, and remains in a critical condition at St Vincent's Hospital in Dublin.