Published Monday, 26 November 2012
Catholic policeman Ronan Kerr was killed in 2011. (© PA)
He was arrested as PSNI are carrying out a number of searches in the Omagh area on Tuesday.
The man is not being held in connection with the murder but other related incidents.
He is currently being questioned at Antrim Serious Crime Suite.
Meanwhile another man from Omagh was arrested by police in England on Monday evening.
Police from the North West Counter Terrorism Unit detained the 22-year-old in Milton Keynes.
A PSNI spokesman said the arrest took place "at the request of PSNI Serious Crime Branch detectives".
He is being questioned at a police station in England.
A lorry and a number of other items have also been seized during searches carried out in Omagh and Cumbria.
The lorry was stopped in the Milton Keynes area.
Constable Kerr, 25, was killed by an under car bomb outside his home in Omagh in April last year.
He was a Catholic new recruit to the PSNI and had recently completed his training when he was killed in the explosion at his home in the Highfield Close area of the town.
Dissident republicans have been blamed.
Police officers and figures from the GAA, of which Mr Kerr was a member, stood together in highly symbolic scenes at his funeral.
His family urged Catholics not to be deterred from joining the PSNI.