A man has been arrested, in connection with an investigation into the attendance of a GSOC investigator, at a party alongside Gerry Hutch.
The man - in his 60s - was arrested in Dublin this morning, on suspicion of disclosing information.
He can be questioned for up to 24 hours.
His home has been searched, with his work phone seized.
The party was held in Dublin the night Mr. Hutch was acquitted of the murder of David Byrne last week.