Klass was willing to argue for his opinions wherever he perceived a challenge. In February 1975 he called the editor of the FBI Law Enforcement Bulletin and "in strong terms laced with sarcasm he derided our publication of the article by J. Allen Hynek, 'The UFO Mystery'". Klass accused the FBI of perpetuating a hoax in the form of extraterrestrial UFOs and referred to Hynek as a fraud. The editor explained to Klass that at no point did Hynek say that UFOs were extraterrestrial in origin, and that UFOs present a unique problem for law enforcement as they are often the first people called when a UFO is spotted. The editor also defended Hynek as a "widely respected scientist... affiliated with a leading university", to which Klass replied, "He won't be for long!" Klass followed up with a letter to the LEB offering a rebuttal article, but the offer was declined.