A man has been released after being held as part of a murder investigation in Dublin.
John Gibson was gunned down at Citywest Shopping Centre around a year-and-a-half ago.
Mr Gibson was shot dead at Citywest Shopping Centre on Fortunestown Lane in Tallaght on September 18, 2017.
The 28-year-old fitness instructor died at the scene from the shooting after being treated for gunshot wounds.
A man in his late 20s was arrested yesterday morning as part of the murder investigation.
He was being questioned at Tallaght Garda Station but was released without charge last night. He was the fourth person to be arrested as part of the investigation.
A file will be prepared for the Director of Public Prosecutions.