CHRISTOPHER Gaffney was murdered because he was selling heroin to the sister of two drug dealers, gardai believe.
Detectives investigating the 37-year-old's gruesome murder are now satisfied he was killed in an apartment in the Blanchardstown area following a bitter row with individuals he had been feuding with over drugs money.
Gardai are investigating if the row sparked from the fact that Gaffney had been selling "gear" to the killer's sister after she tried to kick her drugs habit.
A senior source said: "This is the strongest line in the investigation at the moment – the young woman had tried to give up drugs and had been in rehab.
"But Gaffney continued to sell the stuff to her when she got out and when these two fellas found out, they went mental.
"He had already been in a long-standing cash dispute with them, which was linked to an incident in which Eastern European criminals tried to break into his house a couple of months before he vanished."
While the cause of death has not been definitely established, gardai are working on the theory that Gaffney was stabbed to death at the Blanchardstown apartment – the location of which has not been disclosed.
The investigation has now reached a stage where detectives think it "is highly unlikely" that Gaffney was murdered for his alleged role in a 2010 murder.
He was previously arrested by detectives probing the murder of a young man whose body was dumped in a field, but he was not charged in relation to the crime.