Published Friday, 15 May 2009
The 44-year-old man was detained in Magherafelt.
Officers involved in the investigation are also carrying out searches in Pomeroy and Dungannon in Co Tyrone.
Sappers Patrick Azimkar and Mark Quinsey were shot dead while collecting pizza at the Massereene Barracks on 7 March.
Two pizza delivery men, one a Polish migrant, were wounded in the attack, for which the Real IRA claimed responsibility.
Dissident republican Colin Duffy, 41, was charged with murdering the two soldiers.
In addition to the two murder charges, Duffy was also charged with five counts of attempted murder and one of possessing a firearm and ammunition.