A 21-year-old man was savagely beaten across the face and head with a claw hammer as he slept in his bed.
The victim is a very close associate of gangland murder victim Alan McNally, who was shot dead in a north Dublin pub in 2012.
The young man, who has refused to make a complaint to gardai, lost multiple teeth and suffered horrific facial injuries in the attack.
Gardai from Finglas were called to the incident at around 9am on Sunday and the victim was rushed to Blanchardstown's Connolly Hospital.
It is understood that the young man knew his attacker and has since been released from hospital after spending a number of days receiving treatment.
His suspected attacker was briefly detained by Irishtown gardai for an unrelated matter over the weekend. No arrests or charges are expected in the case despite the horrific nature of the claw hammer attack.
The incident unfolded at the Barry Close estate in Finglas, which is also the location of a 'drugs superstore', which gardai have raided numerous times this year.
The suspected attacker is linked to these drug dealers, according to sources.
He is part of a gang linked to a property that has been raided about six times this year by local drugs squad officers.
Sources say that all types of drugs - ranging from heroin to crack cocaine - are being sold by the vicious mob.
They are not suspects in the Alan McNally murder case and the assault is not linked to that, according to sources.
Meanwhile, a garda investigation is continuing into the murder of the assault victim's close associate, Alan McNally.
Alan, from Cappagh Avenue, was killed on February 2, 2012, after he was shot multiple times while drinking in the Cappagh House pub in Finglas.
The father of three sons - the youngest of whom was six at the time - had only recently been released from prison after serving five-and-a-half years for possession of €200,000-worth of heroin.
Having been at the bar all day, McNally had texted a friend to say he was about to leave when he was attacked shortly after 1.10am. No one has ever been charged but gardai are following a definite line of enquiry in the murder case.