A veteraN drug dealer who is suspected of playing a major role in the gangland murder of Philip 'Philly' O'Toole was being questioned by detectives today.
He was arrested in Bray, Co Wicklow, over the weekend and sources say officers are making significant progress in the probe into the 32-year-old's murder.
O'Toole's body was discovered on Friday at Trooperstown Wood, in Rathdrum, Co Wicklow, after a tip-off to gardai following a search that had lasted two-and-a-half weeks.
Sources say detectives believe he may have been set up by a criminal he thought he could trust.
The man in custody is understood to be a former friend.
A senior source said: "O'Toole had become paranoid in recent months, but he did trust a small number of individuals, including the man in custody.
"They knew each other for years and O'Toole would have seen him as one of his most trusted associates."
The Herald has also learned that vehicles and a property connected to the arrested man have been searched and forensically examined by gardai.
The suspect served a jail sentence for dealing cocaine and cannabis.
O'Toole, from Fassaroe, in Co Wicklow, was abducted and shot in the head.
He had a seven-month-old boy with his partner, Jennifer Kelly.
He was reported missing by his family after he failed to contact them at their home in Meadows Lane, Arklow, on January 7. The following day gardai found his blue BMW three-series coupe, parked at Dargle Avenue, close to roadworks, at Lower Dargle Road in Bray.
The feud that led to his death kicked off when O'Toole's former criminal associates turned on him when he started "sourcing his own drugs from a major Dublin gang".
They also branded him a garda informer and put up graffiti on walls on estates in the town in 2011.
O'Toole survived a gun attack in Enniskerry in August 2011, when he wrestled with the gunman before being shot in the stomach.
He was arrested, but later released, by gardai investigating the shooting of Finglas criminal Glen McGrath (41) outside the Cappagh House pub, in Finglas, in December, 2010.
McGrath -- a former associate of slain gangland boss Paul 'Farmer' Martin -- survived after being shot three times the chest and stomach.