Around 140 gardai and PSNI officers have run the Dublin Marathon in memory of Garda Tony Golden.
The “gentle giant” officer and father-of-three was shot dead while helping a woman during a domestic row in Omeath, Co Louth, earlier this month.
An Garda Siochana posted a photo on Twitter of the runners assembled at the start on Monday morning.
The caption read: “Wearing a black ribbon in remembrance of Garda Golden.”
The 36-year-old was gunned down as he accompanied Siobhan Phillips, 21, to collect her belongings from a house she shared with dissident republican suspect Adrian Crevan Mackin.
Crevan Mackin, 24, also turned his illegally-held Glock pistol on Ms Phillips, who was hospitalised, before killing himself.
Garda Commissioner Noirin O’Sullivan and PSNI Chief Constable George Hamilton attended Garda Golden’s funeral in his home village of Blackrock, Co Louth. Around 4,000 gardai thronged the streets around the church.
Thousands of participants and spectators took to the streets for Dublin’s flagship race meeting, which began at Fitzwilliam Square.
Road closures and traffic restrictions were introduced in the city centre.
Garda Golden was the 88th garda to die in the line of duty.
It has emerged that he had voiced concerns about staffing levels in the Louth policing district where he worked in 2013.
Late on Sunday night, news network RTE reported that he had given a note detailing the low level of policing resources to the Cooley Peninsula Community Alert Group, complaining “about the reduction in Garda manpower and an over reliance on overtime”.
Gerry Adams, TD for Louth, said that figures from Dublin’s ministry for justice show that the numbers of police had dropped from 314 in 2010 to 277 by the start of May2015.