 The recording on a cassette tape ended with a segment from the 1978 single "Thank You for Being a Friend" by Andrew Gold.George Oldfield and other senior officers were informed by the FBI that the creator of the tape was a blatant hoaxer.The US profiling expert Robert Ressler indicated, in his co-written book, "Whoever Fights Monsters", that he contacted them to inform them immediately after he heard the recording.