Irish police watchdog to investigate murder of Garda Tony Golden
The murder of a police officer in the Republic of Ireland by a man from Northern Ireland 18 months ago is to be investigated by a police watchdog.
Tony Golden, a member of An Garda Síochána (Irish police) was killed in Omeath, County Louth, in 2015 as he tried to help a domestic abuse victim.
He was shot dead by County Down man Adrian Crevan Mackin, who had a string of convictions and was out on bail.
Questions have been raised about how Gardaí responded to the risk he posed.
FBI tip off
The Republic of Ireland's police watchdog - the Garda Síochána Ombudsman Commission (GSOC) - confirmed it has begun an investigation into the force's handling of the case.
Irish broadcaster, RTÉ, has reported that the US authorities warned Gardaí that Mackin was importing weapons in the months before the murder.
Mackin's sister told RTÉ's Prime Time programme that she believes he was buying decommissioned weapons and selling them to dissident republican paramilitaries.
The 24-year-old gunman, who had previously lived at several addresses in the Newry area, also had a history of domestic violence.
On the day he murdered the police officer - 11 October 2015 - Mackin shot and critically wounded his own partner, Siobhán Phillips, before killing himself at her house in Mullach Alainn, Omeath.
Garda Golden was unarmed when he accompanied Ms Phillips to the house to collect her things, after she made a statement about violent domestic abuse.
Mackin opened fire as they walked in through the door, killing Garda Golden and leaving the mother of his children blind in one eye.
Before Mackin moved across the border to Omeath, he had been previously convicted in Northern Ireland of gun and ammunition possession and having extreme pornography.
According to RTÉ, months before the murder Mackin admitted to Gardaí that he bought component parts for guns and bombs over the internet.
It reported that, after a tip off from the FBI, cross-border police searches took place in counties Down and Louth.
Mackin was arrested by Gardaí after they found bomb components at his home in Omeath.
The programme obtained access to transcripts of Gardaí interviews, during which Mackin admitted buying the weapons, but refused to comment on alleged links to paramilitaries.
Despite his confessions, prosecutors instructed detectives to charge him with IRA membership - which he denied - as opposed to the firearms offices he had admitted.
Mackin's solicitor at the time, Paul Tiernan, told RTÉ he found it "very strange that someone who had admitted possession of firearms and who had admitted the importation of component parts for firearms should have been treated in this way".
Mr Tiernan added: "In the vast majority of cases, the strongest evidence against people is their own admissions."
The GSOC investigation is expected to include claims that some of the weapons Mackin admitted to importing are still missing.
It is also expected to examine claims by Ms Phillips' family about how Dundalk Garda station handled their initial complaint of domestic violence.
Garda Golden, who died trying to protect her, was hailed as a hero and given a state funeral.
In a statement, a Garda spokesman said the force "is aware that GSOC is undertaking a public interest inquiry into assertions made in relation to the circumstances surrounding the callous and brutal murder of our colleague Garda Tony Golden by Adrian Crevan Mackin.
"As such, we are precluded from comment on such assertions."