'FAT' Freddie Thompson's gang planned the massacre of rivals in a grenade attack on a city pub.
The Herald can today reveal how senior gardai obtained information on the attack.
An informant warned that Thompson gang members were watching their rivals' movements, and had tried to obtain grenades to attack them as they socialised.
The information led officers to mount an 'in your face' campaign, targeting both outfits, to prevent the bombing.
However, senior gardai did not accept that the information was correct, retired top garda PJ Browne has claimed.
Last week, two rocket propelled grenade launchers belonging to Freddie's gang were seized in Co Kildare.
The devices were intended for use in an attack on King Ratt's gang.
But such an attack had previously been planned. A garda informant warned gardai in 2004 that both gangs had planned to use grenades on each other but senior officers at Garda headquarters laughed off the threat.
Former detective superintendent PJ Browne, who oversaw operations against the feuding Crumlin crime gangs for a decade, claimed that the feuding gangs were racing to obtain grenades.
"Senior officers at the force's headquarters were warned by me and some of my then staff over six years ago that a search was under way on the parts of both the King Ratt gang and Fat Freddie's crew to acquire grenades," he said.
"It was intended that which-ever gang got them first, they would try to lure the other gang in large numbers to a pub and when all were assembled and settled a man would enter the property and throw a grenade into their midst -- with the intent that they would all be blown to pieces."
The gang used the codeword 'pineapples' to refer to grenades.
At the time, the feud between the gangs was reaching its peak. A pub murder had already occurred, with the February 2004 shooting of Thompson associate Paul Warren at Grays's pub on Newmarket Square in the south inner city.
The grenade pub plot was planned in retaliation, it is understood.
Meanwhile, four men remain in garda custody after their arrests last Wednesday. The rocket launchers were found along with an AK47 assault rifle, ammunition and cocaine with a street value of nearly €700,000 buried under a shed at Longtown, Straffan.
Gardai at the Organised Crime Unit had been monitoring 'Fat' Freddie's gang for the past month after getting intelligence that an attack of this magnitude was afoot.
The raid was part of Operation Lamp, which has been targeting members of a drug trafficking gang, based in the Crumlin area of Dublin.
The raid on the lock-up in Kildare followed the seizure of another kilo of cocaine at the Naas Road, near Rathcoole, Co Dublin, on Tuesday evening when the organised crime unit stopped two cars and detained four men.
The men are still in custody today at Clondalkin Garda Station, held under Section 50 of the Criminal Justice Act.
It has been reported that the Thompson gang may have obtained the RPGs after striking a deal with dissident republicans, with whom they have had a working relationship since the height of crime war.
The dissidents traded the weapons for drugs which they sold in the North.
A source revealed last week that the RPGs were to wipe out the King Ratt gang.
"A peace talks and drug deal meet was being set up. The intelligence was that two RPGs would be fired at the house once the rivals were inside the room there," a source told the Herald.
It was also revealed that 'Fat' Freddie's operation was aided by a Co Kildare associate of drug boss 'Factory' John Gilligan, who was involved in the importation and storage of the weapons and drugs. He worked with a 32-year-old Dublin man, a close associate of 'Fat' Freddie, based with the boss in Spain.