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heroin bust Retired garda tells how he posed as dealer to bring down kingpin Larry Dunne


Michael O’Sullivan posed as a drug user to infiltrate the criminal network of Larry Dunne

Michael O’Sullivan posed as a drug user to infiltrate the criminal network of Larry Dunne

Michael O’Sullivan posed as a drug user to infiltrate the criminal network of Larry Dunne

Ireland's first undercover drugs cop has revealed how he infiltrated infamous drug dealer Larry Dunne's network which eventually led to the gangster being caged.

Retired Assistant Commissioner Michael O'Sullivan will on RTÉ One on Wednesday night share his experience of how in 1982 he became the first detective to be sent undercover in the fight against drug crime.

His investigations led to a four-year game of cat and mouse, as he set out to bring down Ireland's first heroin baron, Larry Dunne.

In 1982, he was a young detective about to embark on what, for Ireland, was an entirely new type of policing operation. Michael was sent undercover to infiltrate the drug-dealing operation of the country's first drugs baron.

In The Case I Can't Forget, he tells the extraordinary inside story of this ground-breaking investigation, and explains how the case stuck with him for the rest of his career.

In the early 1980s, a new narcotic hit the streets of Dublin for the very first time - heroin.


Larry Dunne

Larry Dunne

Larry Dunne

Neither the gardaí nor the communities where the drug is sold were prepared for the consequences. Within months, the capital was in the grip of a heroin epidemic.

In this episode, a cast of dynamic characters who lived through that era describe how stable working- class neighbourhoods were torn apart within a matter of months.

Children as young as 12 were recruited as dealers. Young men and women, newly addicted to heroin, were stealing from their own parents and grandparents, to pay for their habit.

Inner city flat complexes were turned into drug-dealing fortresses, impenetrable to gardaí.


The man responsible for this chaos was Larry Dunne.

Dunne's background was in bank robberies. But a Garda crackdown on such crimes forced Dunne to look for another opportunity.

He found it on the other side of the world, where a revolution in Iran and the Russian invasion of Afghanistan, led to Europe being flooded with heroin.


Larry Dunne attending court

Larry Dunne attending court

Larry Dunne attending court

Dunne took his chance and established Ireland's first organised heroin importation operation.

He recruited dealers across inner city Dublin. Within months, he established himself as the godfather of the Irish drug trade. He becomes an unmissable figure, as he is chauffeured through his working class neighbourhood in a Rolls Royce.

Michael's job was to pose as a drug user, infiltrate the upper echelons of Dunne's gang, and gather evidence to arrest and charge Larry Dunne with drug offences.

His team of undercover mock drug addicts became known as 'The Mockies'.

"Nobody had been applied in an undercover capacity working in drugs in Ireland. It was a dangerous, challenging environment," Michael says.

He describes his colleagues being assaulted, stabbed with syringes and even having flesh bitten off during street arrests.

"It was very violent, and a case of trying to make the best decision as the case unfolded at street level. Violence was just an occupational hazard."

In the early 1980s Dublin's user population exploded to over 5,000, with dozens of young people overdosing and dying.

There was a phrase associated with Larry Dunne on the streets of Dublin: 'Larry Doesn't Carry'.


Michael's challenge was to find Larry Dunne actually in possession of narcotics. Dealer by dealer, Michael worked his way up Dunne's drug-dealing pyramid, intent on arresting the boss himself.

Michael's undercover investigations delivered a breakthrough. He discovered Dunne and his inner circle had started using the drugs they were selling. For Michael, this was Dunne's fatal flaw.

Intelligence said drugs were being held in the Dunne family home. A rapidly organised search of the property uncovered IR£60,000 of heroin stashed in his young daughter's bedroom. Michael now had the evidence he needed to arrest Dunne and charge him with drug trafficking. But the master criminal proved elusive. On the first day of his trial, he escaped from court and disappeared.

Dunne was eventually captured abroad and was sentenced to 14 years in jail. He died earlier this year at the age of 72.

  • The Case I Can't Forget is on RTÉ One on Wednesday at 9.35pm

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