Investigators are seeking footage and witnesses in a bid to determine the circumstances behind the brutal killing of Detective Garda Colm Horkan.
Officers are also checking recordings of a call for backup the detective is thought to have made after he confronted his assailant in Castlerea, Co Roscommon, just before midnight on Wednesday.
The murder investigation team is also examining how his attacker managed to take the detective’s official handgun and shoot the 49-year-old officer.
There are indications that all 15 rounds were discharged from the handgun, but it is thought four hit the garda and that two other bullets grazed him.
The experienced garda was on a single-person patrol in Castlerea when he confronted a motorist following calls to the station that a stolen motorbike was being driven erratically in the area.
Local sources said Det Gda Horkan assisted uniform gardaí who were called to deal with the complaints.
Speaking outside Castlerea Garda Station, Commissioner Drew Harris said: “There were various calls ongoing, but Detective Garda Colm Horkan was engaged on anti-crime patrol around ongoing work in respect of burglary patrols, anti-crime patrols, drug patrols. There were incidents ongoing but he was on general anti-crime patrol."
Det Gda Horkan had 24 years’ service, first in Finglas, north Dublin, before spending 21 years in Roscommon, the bulk in Ballaghaderreen sub-district station and the last month or so in Castlerea district station after he was promoted to detective.
He spotted the driver of the motorbike near the junction of Main Street and Patrick Street and a physical altercation developed.
Commissioner Harris said an initial conversation deteriorated into an altercation and the detective’s “service pistol was used against him” and he was severely wounded.
Paramedics from a nearby ambulance gave prompt medical assistance but he died at the scene.
The suspect was arrested nearby by uniformed gardaí and he was detained under Section 30 of the Offences Against the State Act, allowing for up to 72 hours’ detention.
The man, described as a local, was seen by a doctor. The individual, aged in his 40s, is well known to gardaí generally and also known to social services.
Several sources said that the full 15-round magazine in Det Gda Horkan’s handgun was discharged, but it is thought that four shots hit the garda at close range and that two others grazed him.
This could not be confirmed officially and gardaí stress it is under investigation.
Sources said that during the confrontation, Det Gda Horkan rang for back up and that he pressed the emergency button on his official radio which records the next 30 seconds – potentially capturing the shooting.
There were also reports that a Garda traffic car may also have footage of relevance.
Commissioner Harris also appealed to people in the area who might have footage to come forward and added: “We understand perhaps an image was shown on social media very shortly afterwards and we would ask that person to come forward and present that footage to us – it could be very useful and important to this investigation.”