The remains of Detective Garda Colm Horkan will be brought to his family home in Charlestown this evening.
People will get a chance to pay their respects as they're brought through Ballaghaderreen, where he worked in the past.
Preparations for a state funeral are under way.
A man remains in custody in connection with the murder of the 49-year-old in Castlerea, Co Roscommon, on Wednesday.
Bishop of Elphin Kevin Doran is urging people to be united at this time.
