A detective heading the Claudy bombing investigation has travelled to the US to question a suspect detained by the FBI.
The confirmation came as the PSNI failed in an unprecedented legal bid to be allowed to view a television documentary into events surrounding the blasts before it is broadcast.
Nine people were killed in bomb attacks on the Co Londonderry village in July 1972.
Earlier this year a Police Ombudsman report found senior RUC officers conspired with the Government and the Catholic Church to protect a Catholic priest suspected over the attack.
Ahead of last night's planned BBC Spotlight programme lawyers for the Chief Constable sought a High Court injunction.
They wanted a senior detective to be permitted to view the documentary before it was screened.
One concern outlined was that suspects or witnesses in the investigation could be named in the documentary.
Barrister David Dunlop said the police investigation into the bombing remains active, and disclosed that a Chief Superintendent went to the USA last Friday to interview a suspect.