While hunting Soviet spy, FBI feared angering Scientologists - 2017-02-23
A Priority Teletype from the FBI's Legat in London to the Director outlined an interesting problem - the Bureau had been asked to help with a case involving Stig Bergling, a Swede who had apparently been spying for the Soviets, and a woman in the Tampa area might have information as to his whereabouts.
There was just one snag - they were afraid it might lead to a confrontation with the Church of Scientology.
Despite the concerns, the interview went forward. The details of this woman's involvement are mostly redacted. In a subsequent interview, the mystery woman explained that she had only ever spoken to Stig Bergling AKA Stig Sandberg once, and that was on the phone.