The PSNI have been accused of using the search of the home of leading republican hardliner Gary Donnelly as a cover to remove sophisticated electronic equipment.
Mr Donnelly, a leading spokesman for the 32 County Sovereignty Movement (32CSM), is being held on remand charged with membership of the breakaway Real IRA.
One person was arrested during the search of Mr Donnelly’s home in Derry’s Creggan area on Sunday. The 32CSM said the house belonged to Mr Donnelly’s partner, Orla Brady.
Donnelly was arrested on March 16 along with three other men close to the Derry/Donegal border. The four men have been held on continuing remand facing the charge of membership of an illegal organisation and will face the non-jury Special Charge Criminal in Dublin on a future date.
The 32CSM has described a series of such arrests this year as a form of internment without trial. A spokesman also said the weekend operation was to remove electronic spying equipment in advance of work being carried out at the house.
Campbell is one of those named in the ongoing civil action at the High Court in Dublin by the victims of the Omagh bombing in August 1998.
The High Court heard this week that the FBI has refused to let its agent David Rupert testify at the civil action because of the killing three years ago of republican informer Denis Donaldson.
US authorities have claimed the risk against Rupert, who infiltrated the Real IRA, would increase if he became involved in the trial in Belfast because of the “oxygen of publicity” it would cause.
Donaldson was killed by a mystery attacker in a remote part of Donegal after he confessed to informing on Sinn Féin and the republican movement on behalf of British forces for over twenty years.
It has been reported that Rupert received millions of dollars in benefits to help bring down the Real IRA, and that he was paid for another three years after the 2003 trial of Michael McKevitt in Dublin.
It is still not known what knowledge Rupert possesses in connection with the Omagh bombing, which killed 29 innocent civilians despite the police forces having foreknowledge of the attack.