Gardai on red alert as ex-INLA kingpin returns to Dublin.
Duffy was sentenced to life imprisonment in 2010 after pleading guilty to killing a British soldier in 1992.
A judge jailed him for a minimum of 24 years – but Duffy served just two years after claiming the killing was an 'act of terror' under the Good Friday Agreement.
He is considered an especially dangerous individual and came to notoriety after leading the INLA in the notorious Ballymount Bloodbath in 1999.
During the incident, Duffy's INLA confronted a Dublin drugs gang in Ballymount, which led to the death of INLA man Patrick Campbell.
The row saw the INLA group strip, beat and interrogate the criminal gang, holding drills to the backs of their knees while threatening to shoot them.
Duffy and another man subsequently pleaded guilty to the unlawful possession of a shotgun and falsely imprisoning the four men at Ballymount Road Industrial Estate.
Duffy was later jailed for nine years by the Special Criminal Court.
Following his release in 2007, he set about reorganising his INLA gang, focusing on extortion and taking over from drug gangs in the Dublin 8 area.
In June 2008, he was arrested outside the home of a prominent Cork businessman after gardai foiled a suspected kidnap.
He was charged with INLA membership and remanded in custody.
In 2009, he publicly denounced the INLA and pleaded guilty before the Special Criminal Court to membership of an illegal organisation. It is understood he has been subject to death threats since distancing himself from the INLA.
He was jailed for four years before being arrested under a European Arrest Warrant for the murder of Sgt Michael Newman, who was shot dead in Derby in 1992.
After completing his sentence for INLA membership in April 2010, he was extradited to Britain, where he pleaded guilty to the murder of Sgt Newman.
Although sentenced to life, he was freed after two years.
release
Before Duffy was jailed in 2009, he was involved in a turf war with gang boss 'Fat' Freddie Thompson (32).
In the intervening years, Thompson has relocated to Spain, but sources feel his brother Richie could be under threat following Duffy's return.
Since his release last week, Duffy has gone back to the south inner city home of his partner and their two children, in close proximity to the Thompson family.
After his return to Dublin, he travelled to Tallaght to meet an associate in a pub.
With Thompson out of the country, the RIRA still reeling from the murder of Alan Ryan in north Dublin and the murder of Eamon Kelly, there is now a power vacuum in Dublin – one of which Duffy could take advantage.
Officers in Tallaght are said to be particularly concerned about Duffy's meeting there with an associate.
Following the reorganisation of his INLA gang in 2007, he decided to target Freddie Thompson, taking over security at a number of licensed premises and supplying drugs.
He crossed swords with three drug dealers who were supplied by Thompson, demanding protection money from them.
Duffy and Thompson subsequently had a row on Francis Street, with Duffy telling the crime boss he was staying in the area.
Thompson was threatened he would be killed if he did not leave the country.
