Questioning of a 51-year-old criminal who gardai believe has key information about the murder of dismembered teenager Keane Mulready-Woods was suspended yesterday so he could receive medical treatment.
He was being questioned at Drogheda Garda Station as officers continue to build a strong case against several suspects.
It was expected that the suspect would either be charged or released today after his arrest last Thursday by armed officers.
However, this may now be delayed after his questioning was suspended.
A 38-year-old suspect who was arrested at the same time was released from custody in Balbriggan Garda Station early yesterday.
The Drogheda criminal who was receiving medical treatment last night is considered a key member of the anti- Maguire mob and is suspected of having vital information about Keane's barbaric murder.
A property in Rathmullan Park, Drogheda, was searched over a number of days after the murder and gardai believe Keane was killed there.
The arrested man was a close associate of feud murder victim Keith Branigan and is suspected of destroying evidence at the property.
Gardai also detected blood "soaked into the floorboards", and DNA testing has linked the teenager to this house, according to sources.
Furniture belonging to the man was found burnt in a green area nearby, while burnt clothing was also recovered.
He was also allegedly caught on CCTV in the aftermath of the murder buying items gardai believe helped cover up evidence linked to the killing.
A source said the suspect was closely linked to Branigan while also being a "trusted" associate of the 25-year-old mob boss leading the anti-Maguire faction who is currently on the run in Spain.
Branigan was the first fatality in the Drogheda feud when he was gunned down in Clogherhead, Co Louth, last August.
"The arrested man is very much suspected of helping the gang who carried out the murder, and a large amount of evidence has been recovered," one source said.
"He has known links to the anti-Maguire gang and would be considered a trusted member of the crime group."
Keane was working for both sides of the Drogheda feud but was more closely aligned to the Owen Maguire-led faction.
Gardai believe he was killed by the anti-Maguire grouping.
A file will now be prepared for the DPP on the 38-year-old Drogheda criminal who was released without charge yesterday.
He is a major drug user and previously served jail time over a stabbing attack on an innocent man.
He is suspected of having played a major role in luring Keane to the house in which he was butchered on the night of January 12.
It is understood he was also questioned about his alleged links to a stolen car that was abandoned and set alight in Ballybough.
Keane's severed head was found in the burnt-out vehicle.