Gardaí are investigating whether a full round of ammunition was fired at 49-year-old Detective Garda Colm Horkan last night.
Late last night he was on patrol in Castlerea Co. Roscommon when he stopped to speak to a man who had recently been in contact with Gardai.
The conversation developed into a physical altercation, during which the man took possession of Garda Horkan's gun.
An entire round of bullets was fired and the detective has shot a number of times.
He was pronounced dead at the scene.
Garda Commissioner Drew Harris paid tribute to Garda Horkan at the scene this afternoon.
Detective Garda Colm Horkan was known in the community as a gentleman committed to helping other people.
Fr John McManus says it's a difficult time for everyone.
The Taoiseach has offered his sympathies to the friends, family and colleagues of Detective Garda Colm Horkan.
Leo Varadkar says the nation is grieving following his death.
Meanwhile, the Justice Minister has expressed his shock and sadness at the shooting.
Charlie Flanagan says he wants to express his sympathy to the 'parents and family of the brave Garda who died doing his duty serving his community and to the wider family of An Garda Siochana'.
Local Roscommon Fine Gael TD Frank Feighan says the community is in shock.
Further tributes have been paid to Detective Horkan as he is described as an experienced detective who was greatly respected.
President Michael D Higgins says the death of a detective garda while on duty has shocked us all
President Jim Mulligan from the Garda Representative Association said he was a greatly respected colleague.
Sinn Fein’s Mary Lou McDonald said it’s as a sad and difficult day for gardai says while Fianna Fail’s Jim O’Callaghan said Colm Horkan’s death wasn’t just an attack on one individual but an attack on civilised society.
