The 22 year old, who is well-known to Gardai, has a string of convictions.
Gardai are keen to interview the man after the recent attack on a 32 year old victim outside McCarry’s Bar close to Gallagher’s Hotel last weekend.
The father-of-two had just returned from America where he lives when the attack happened.
It is believed the man was set upon when he refused another man a cigarette.
He was slashed in the head, face and chest with a knife and was rushed to Letterkenny General Hospital before being transferred to St James Hospital in Dublin.
The man has since returned to America where he will receive further medical help.
Gardai are anxious to speak with the alleged attacker but it is believed he has skipped across the border to Northern Ireland.
Just hours before the attack, the suspect had been due to appear at Letterkenny District Court but was not there when his case was called.
Judge Paul Kelly issued a bench warrant for the man’s arrest.
Just hours later the innocent father of two was attacked during broad daylight on Letterkenny’s Main Street.