I've been intrigued by the current case in Portugal where Madeleine McCann's parents are trying to prevent the police officer who investigated the case from publishing a book. The book claims that Madeleine is dead, the McCanns were responsible and there are no other credible suspects. The McCanns state that there is no credible evidence to support this claim, the book is defamatory and interferes with an ongoing investigation.
I don't know the rights and wrongs of the case, but I do have some experience of how the British police think about such matters and it certainly leads me to have some sympathy with the McCanns. I know a few people who are police officers quite well. Some of them I've known for many years. One of my friends fathers was a senior detective at Scotland Yard. When the Birmingham six and Guildford four cases first emerged, I read an article which stated categorically that the evidence had been fabricated and they'd been stitched up. I put this to my friends father, who reared up at me and told me that the police would never do such thing. He asssured me that in such a high profile investigation the rules would have been followed to the letter. He said that there was "plenty of evidence which couldn't be presented in court which conclusively proved their guilt". Sadly for the victims, this was later proven to not be the case at all.
A few years later, Rachel Nickell was murdered. The prime suspect, Colin Stagg suffered an elaborate sting operation to try and elicit a confession. When he eventually appeared before a court, the evidence was unceremonially thrown out. Another friend who is a police officer worked on the case. He assurred me that Stagg was guilty, their was a stack of evidence that again "couldn't be produced in court" that proved Stagg was guilty. He assurred me that Stagg's acquittal was a "serious miscarriage of justice". Last year the real murderr of Rachel Nickell was found guilty. I asked my friend about this "compulsive evidence". He rather sheepishly admitted that he'd got it wrong. He explained that Stagg "wasn't a nice person and he was well known to the local police". I pointed out that there is a huge difference between being a "not nice person and a psychopathic killer". I then asked him if the real killer hadn't emerged he'd still have believed that Stagg was the killer "erm, I suppose so".
Sadly the truth is that the police are human. They don't always get it right. I doubt that Portuguese policemen are any better at being "psychic" than British ones. That is why we have courts and that is why courts decide innocence or guilt based on evidence, rather than the hunches of coppers. That is also why we have the principle of "innocent until proven guilty". There are some people who will always believe that the McCanns are hiding something. Who knows what will eventually emerge, but it is clear as day to me that history tells us that just because a copper has a hunch, doesn't mean anything. The most disturbing thing about the Stagg case is that because the police were so obsessed with Stagg, the real killer was missed for many years. That is my biggest worry about the McCann case.