Colm Horkan had served as a guard for 24 years.
Garda Commissioner Drew Harris has issued a statement following the fatal shooting of Garda Detective Colm Horkan in Castlerea, Roscommon shortly before midnight on Wednesday.
"I am deeply saddened by the death of my colleague Detective Garda Colm Horkan," Harris said.
"My thoughts, and the thoughts of all personnel in An Garda Síochána, are with the family, friends and colleagues of Detective Garda Colm Horkan at Castlerea Garda Station and the Detective Unit he served in."
Colm Horkan, from Charlestown in Mayo, had served in An Garda Síochána for 24 years.
Harris went on to say: "Today is a terrible reminder of the significant sacrifices, including the ultimate sacrifice, that Gardaí make to keep people safe.
"I want to thank the local community in Castlerea and the country as a whole for the support they have shown to An Garda Síochána and individual Gardaí even in the short time since the incident."
Colm Horkan is the 89th Garda to be killed in the line of duty, and the first since 2015.
Harris also appealed to anyone for witnesses to the incident to contact Castlerea Garda Station at 094 962 1635.
The incident is being investigated as a murder, and a man has been arrested and is detained at Castlerea Garda Station.
Tributes to Colm Horkan have been paid by Taoiseach Leo Varadkar, President Michael D. Higgins and Minister for Justice Charlie Flanagan.
