When studying wrongful convictions, there are many causes. The most routine causes are witnesses who are either mistaken or who have a motive to lie. For example:
- Faulty eyewitness identification
- Guilty parties putting the blame on others
- Incompetent expert witnesses ( liars-for-hire )
Then we have coerced false confessions ( or even confessions that never happened ). I suspect that with recording of suspect interviews, such confessions are now relatively rare.
Next, we have innocent people who lie, which is not exactly a false confession, but can easily cause a wrongful conviction. Examples are self-defense cases where the killing is not immediately reported, lying about being at the scene of a crime.
Then we have cases where there are ambiguous suspicious circumstances. For example a gun being stolen, which might be the murder weapon. A person being a prime suspect ( perhaps simply by being at the scene ). It can be a strange occurrence that has no obvious innocent explanation ( perhaps the Owl attack in the Michael Peterson case ). Or an event that might or might not be an accident (often the death of a child).
Then there is police manipulating evidence, coercing witnesses, suppressing evidence favorable to the accused, or not investigating alternative theories, to get a conviction.
Finally, we have cases where there is some combination of the above causes.
When investigating an alleged wrongful conviction, after establishing the facts, the key is to identify the causes.
… To Be Completed …