Gun gang members who uploaded pictures of themselves to the internet will face prosecution.
Irish detectives already know the identities of all those involved and have seized several weapons.
It's understood gardai contacted Facebook as part of the investigation into the Sligo-based gang.
Images from the 'Fort Hill' drugs gang were uploaded to Facebook via a mobile phone registered to one of the suspects.
Masked men holding guns and axes were pictured in several of the photographs.
"The pictures were part of an attempt by certain elements in the Forthill area of Sligo to intimidate the community," said one source.
"Ironically, the pictures could end up putting those same gang members behind bars. It shows how incredibly stupid some of them really are."
Gardai have now seized all the weapons featured in the pictures after a series of raids in the Sligo town area. They also recovered drugs with a street value of €50,000.
Residents of Forthill said they were delighted the Facebook stunt had backfired on the gang.
"They (the gang) were trying to intimidate members of this community into turning a blind eye to their drug dealing," said one resident yesterday.
"Hopefully the guards have enough evidence to take them off the streets."
The gang -- calling itself the Fort Hill Ultras -- deals in a range of drugs including cocaine and diazepam.
It's understood gardai are awaiting for a report from Facebook before sending a file to the Republic's DPP.