A man has been arrested in connection with the murder of Derek Coakley-Hutch.
Gardai said the man, in his mid-twenties, was taken into custody in Dublin on Friday morning.
He is being held at Ronanstown garda station.
He is the third person to be arrested in relation to the investigation.
Derek Coakley-Hutch, 27, was shot dead on January 20 last year near Wheatfield prison in west Dublin.