Gardaí are questioning a man in his mid 40s in relation to the murder of Dean Johnson in Dublin last year.
The 20-year-old died after being shot while sitting in a car on Moorfield Avenue in Clondalkin on May 25, 2011.
This morning, investigating gardaí arrested a man and he is now being held at at Ronanstown Garda Station under Section 30 of the Offences Against the State Act.
It follows the arrest of a 23 year old man on Monday night in Co Wexford in relation to Mr Johnson's death.
He is still being questioned by gardaí at Lucan Garda Station.