The 40-year-old criminal, who was previously himself the victim of a highly publicised crime, remains in garda custody this evening.
It is understood he had attempted to clean up the scene of the stabbing in Kildare before being disturbed by a third party.
He is being held on suspicion of the murder of Jeffrey Jackson (50), who was stabbed to death at an apartment in Kilcock on Thursday afternoon.
The victim, who is originally from Cedar Park in Leixlip and known to the suspected killer, was found with multiple stab wounds to the neck and torso.
At this stage, gardaí believe the men had only been in the apartment together for a short period before the fatal stabbing and are probing a possible motive for the attack.
The Irish Independent understands the suspect was detained for public order offences in a different county that day but released from custody in the hours before the killing. He subsequently made his way to the apartment in Kilcock, where he was present with the victim for a short period of time before the attack.
Emergency services were alerted to the scene in shortly after 4pm on Thursday.
“A witness called emergency services reporting the stabbing,” a source said.
“The suspect was at the scene when gardaí arrived and it appears he was initially making efforts to clean the scene and remove any evidence of the crime when he was interrupted.”
The man in custody has previously served a lengthy jail term for drug-trafficking offences. Gardaí are continuing to question him after he had earlier been given medical treatment for issues unrelated to his arrest or detention.
A senior investigating officer has been appointed to oversee the inquiry, while a family liaison officer has been appointed to assist the relatives of the victim.
Gardaí remained at the scene on School Street this evening as a forensic examination continued.
A garda spokesman said: “Gardaí are investigating a fatal assault of a man that occurred between 3pm and 4pm on Thursday, February 8, 2024, at a residence on School Street in Kilcock, Co Kildare.
“A man in his 40s has been arrested on suspicion of murder as part of this investigation. He is currently detained under the provisions of section four of the Criminal Justice Act 1984 at a garda station in Kildare.
“Gardaí are appealing to any persons who were in the vicinity of School Street between 3pm and 4pm and observed any activity which drew their attention to come forward.
“Any road users who may have camera footage (including dashcam) and were travelling in the vicinity of School Street between 3pm and 4pm are asked to make this footage available to gardaí.
“Anyone with any information is asked to contact Leixlip garda station on 01 6667800, the Garda Confidential Line on 1800 666 111, or any garda station.”