A main target of the Criminal Assets Bureau (CAB) has become engulfed in cocaine- fuelled paranoia.
The 30-year-old criminal's car dealership was raided by gardai last year.
Since then, his behaviour has become increasingly erratic, and he insists on checking the phone of anyone he meets, the Herald has learned.
The south inner city man, who was previously jailed in relation to a 2010 tiger kidnapping, has links to many of the capital's biggest gangs, including the Kinahan cartel, a Clondalkin-based murder gang and the west Dublin heroin-dealing outfit known as 'The Family'.
However, since he was raided by the CAB last October, sources said he has "lost the plot" with paranoia.
"This fella has gone off the rails altogether - he thinks he is being watched all the time and that everyone is a garda informer. He is grabbing phones off people," one source said.
"There has been a number of occasions where he has been at house parties and demanded that everyone in the room hand over their phone so he could check that they were not gardai or were not saying anything about him on their devices."
It is understood the gangster has been consuming vast quantities of cocaine since the CAB raided his business six months ago.
"Of course the coke is not helping his mental state at all, he really has gone downhill since those raids happened. People are afraid of him," the source added.
The gangster's erratic behaviour has been compared to that of notorious Eamon 'The Don' Dunne before he was shot dead in a pub in April 2010.
"Like Dunne was before he was killed, this fella is seeing enemies everywhere even where they don't exist," a source said.
It is understood that the "well-connected" criminal got involved in the car trade in 2013 after serving just over two years in jail for crimes linked to a terrifying tiger kidnapping, in which a bank worker's family were targeted in south Dublin.
Last October, the CAB seized up to 10 top-end cars from his business and several documents were also recovered.
However he was not arrested during the high-profile operation. Despite the garda crackdown, his company is back in business under a new name.
The paranoid mobster has been living in an expensive city apartment. Business listings for his company said it is involved in the sale of second-hand motor vehicles, and it still stocks several high-end motors including Mercedes, BMWs and Audis.
The CAB operation last October was part of a garda inquiry into a west Dublin gang, which has been a high priority for national and local garda units.
The suspected leader of the gang, who is 31, is well-known to gardai having served a lengthy prison sentence after being caught with cocaine.
The gang has close links to the Kinahan cartel, who are leading Dublin's deadly gangland feud, which has so far claimed 11 lives.
Over 20 properties and businesses were searched, with 46 cars removed by gardai. Another car sale company in west Dublin was also raided.
Four high-end watches worth at least €35,000 were seized, along with around €50,000 in cash.
Also taken for inspection were "considerable amounts of documentation and electronic equipment".
It is believed all the vehicles seized last October were taken to the Curragh Camp, where gardai previously stored cars seized from the Kinahan cartel during previous raids.