I was at a seminar last week and watched a presentation on false confessions. A lot of statistics were presented, based on a number of studies and research. Most people have a difficult time acknowledging that an innocent person would confess to something they didn't do. The facts however show that it happens fairly often. When you think about it, it shouldn't be too surprising. Police officers are trained in interrogation, and some of them are really good. They know all the right buttons to punch to get people to admit to things.
One of the more interesting things I learned was a fact about John Reid, who developed the most popular - and prevalent - technique for interrogation. Police officers everywhere are trained on the Reid technique, and it's been shown to be extremely successful. Reid became famous for obtaining confessions in difficult cases, which is where he developed his techniques. It turns out that the case which really thrust him into the national spotlight was a false confession. Unfortunately, it took 40 years to discover he got the wrong person to confess.
There's a joke that any prosecutor should be able to convict a guilty defendant, but it takes real skill to convict an innocent defendant. The same could be said for interrogators; it takes real skill to get an innocent person to confess.
The statistic I found startling was that almost 60% of people believe police can't lie to you. That's absolutely false. Courts long ago held that police are allowed to lie and manipulate the truth when questioning a suspect. I've seen a number of cases where the officer told the person that his co-defendant already implicated him, so he needs to make sure his side of the story is out there. The truth often is that the co-defendant is adamantly denying any involvement. They can even tell you they have fingerprints or other physical evidence.
So if you are ever questioned by the police, don't assume they are being truthful just because they are police officer. Chances are they aren't.