As a Pagan I don't think that any book has outraged me more than The Rachel Files by DI Keith Peddar - as part of the witch hunt (and I mean this literally) against Colin Stagg the police made 'extensive enquiries' into Wicca...here's a quote from the book:
"In 1973, the cult was featured in a film staring Edward Woodward and Britt Eckland, called The Wicker Man. Woodward played a detective sent to a Scottish island to investigate the disappearance of a schoolgirl. He unearthed a terrifying world of devil worship and pagan rituals, and was eventually burned alive inside a huge figure of a man woven out of wicker"
What sort of idiot bases their understanding of a religion on a fictional movie?
Of course after this the odious Paul Britton created the 'honeytrap' that lead to both men being disgraced. They based their entire operation on a misunderstanding of paganism and persecuted an innocent man who was later cleared by DNA and a confession from the real killer - a man that Paul Britton had also profiled.
Fascinating book though, if only for the opportunity to profile the author - an officer who became fixated on one man and through through his ignorance shamed himself and his profession. This book is jaw-dropping because of the complete stupidity of the investigators, the details of police incompetence, and utter failure to follow basic procedures and common sense.