The funeral of Garda Tony Golden has been taking place at St Oliver Plunkett Church in Blackrock, Co Louth.
Dissident republican suspect Adrian Crevan Mackin is thought to have killed the officer as he tried to help his former partner collect her belongings from his house.
The shooter then turned the gun on himself. The murder-suicide in the quiet, seaside village, as most of Ireland was watching a Rugby World Cup qualifier, has rocked the country.
Fr Pádraig Keenan spoke to the gathered, which included representatives of all Christian denominations, senior police officers and the Irish President Michael Higgins and his wife.
He said: "The magnitude of what took place brings to mind all those who have been affected in so many ways.
"Tragically it resulted in the cold blooded murder of Garda Tony Golden in the line of duty.
"Murder is evil, murder has no place in our society. Murder must stop. All forms of violence must stop.
"He like all the others is mourned by the entire nation.
"His murder brings to mind once again all the families and communities that have been affected on our island.
"Garda Tony's death once again reflects how North Louth and the Cooley Peninsula have been affected by the tragic history of the Troubles on the island of Ireland, and especially the murder of Detective Garda Adrian O'Donohoe, three years ago at Lordship Credit Union in Bellurgan.
"Too many hearts have been broken, and lives shattered. I say on this day, from the depths of my heart - and I am sure I speak for all people of goodwill - when I say that there is no place for violence in our society, violence is wrong, always wrong.
"Garda Tony was very happy in the walk of life he had chosen, initially in Cabinteely in Dublin, and for the last six years in Omeath.
"Tony was so proud to serve the community of Omeath. As one person from Omeath put it to me in recent days, he was "our garda", and to a person amongst his family and colleagues, all are immensely proud of Garda Tony and his selfless nature - proud of everything he lived for, worked for and stood for.
"Tony Golden was a much loved role model in our community."