Three of the men arrested yesterday in relation to the ongoing investigation into the 6 March shooting in Blanchardstown have been released without charge. The fourth man remains in garda custody.
The four men were arrested after a man in his 20s was shot and seriously injured as he sat in his van in traffic on Blakestown Road in west Dublin.
The attack is believed to be part of an ongoing feud in the area.
Three men in their 20s and 30s were arrested in Dublin following a number of searches in the Hartstown area of Clonsilla and Blanchardstown, assisted by the garda Armed Support Unit and members of the Defence Forces.
As part of the operation, detectives also conducted a number of searches in Limerick and one man was arrested.
Army engineers, using ground-penetrating radar, also found a container with around €9,000 in cash buried around one metre underground.