A second person has been arrested by gardaí investigating the murder of Tristan Sherry in Blanchardstown, Dublin on Christmas Eve.
A male is being detained at a garda station in west Dublin.
The arrest comes days after a 22-year-old man appeared in court charged with the murder.
Mr Sherry died after he was assaulted and stabbed during a gun attack at Browne's Steakhouse in Blanchardstown.
Mr Sherry, who was the gunman, was tackled at the scene, disarmed, stabbed several times and fatally injured.
A man in his 40s who was shot during the incident remains in hospital fighting for his life.
Last Saturday, 22-year-old Michael Andrecut, with an address at Sheephill Avenue in Dublin 15, was charged with his murder.
He was brought before a special court sitting and remanded in custody.
