BAIL checks were not carried out on a man who went missing while facing charges linked to the murder of David Black due to a broken buzzer at his block of flats and a combination of computer issues and human error.
Damien Joseph McLaughlin (40), from outside Ardboe in Co Tyrone, was due to stand trial this month on charges including aiding and abetting the prison officer's killing.
However, it emerged in December that he had not been seen by police for weeks.
A European Arrest Warrant has now been obtained for Mr McLaughlin, the chief constable has told the Policing Board.
Mr Black (52), from Cookstown, Co Tyrone, was shot dead by dissident republicans as he drove along the M1 on his way to work at Maghaberry Prison in November 2012.
In a written answer to the Policing Board, chief constable George Hamilton said: "Inquiries have been made with the courts and as a result a European Arrest Warrant has been obtained, bail has been revoked and an arrest warrant has been issued for Mr McLaughlin."
Mr Hamilton said since December police have carried out "several searches, interviews of associates and family members, CCTV enquiries and media appeals".
Detectives have also liaised with law enforcement agencies across Europe, including gardaí and Europol.
He said officers first noticed on November 18 last year that the entry buzzer to Mr McLaughlin's address at a block of flats in west Belfast was faulty but he signed bail at a police station the following day - the last time he was seen by officers.
Mr Hamilton said police contacted Public Prosecution Service barristers who informed Mr McLaughlin's solicitor about the issue.
However, he added: "In the period between November 23 2016 and December 23 2016 there appears to have been a breakdown in the monitoring of the bail by police."
The chief constable said: "Whilst the issue of the entry to the block of flats for curfew checks was being examined this was not joined up with the fact he was not now signing at the police station as required."
He said a computer process was shown to be ineffective in highlighting bail breaches in a timely fashion and human error had contributed to a breakdown in communication.
The Police Ombudsman has begun an investigation to establish whether there were any failings in police conduct or systems in the management of McLaughlin's bail conditions.
Mr McLaughlin, from Kilmascally Road near Ardboe, had initially been fitted with an electronic tag while on bail but was permitted by a court to remove it in December 2014 despite strong police objections.
Mr Black's family have said they feel betrayed by the criminal justice system.
