Ethical Situation...
Ok, imagine a situation...
Lets say you are a chief of police in a city or a town, and your whole career you've been truing to catch an organized crime leader. This person you believe is a drug dealer and weapons smuggler, however you've never been able to catch him due to the lack of evidence against him...
Now lets say murder happens, and you arrest that same person for murder, and he is off to the courts to be tried for it. You have finally caught biggest crime leader of your town/city...its what you've been wanting to do for years...this was your goal. If he is convicted, for this murder he will serve a life in prison.
Few hours before you are set t to go to the court, you get a letter of confession. A letter is from the real murderer, confessing to the murder. In the letter the person also says that by the time the police are reading this, he would have committed a suicide...you send few people over to investigate, the prison has really committed suicide, and in the letter he has described the crime so vividly and has given the details of the murder, no one apart from the murderer could have possibly known.
You are now totally convinced that this was the killer and the prison you arrested (and wanted to do so for years) is totally innocent.
So what do you do now....
Do you destroy the letter and pretend like nothing happened, and let the innocent prison go to jail for life for something he didnt do, even though hes a crook?
or
Do you show the letter as an evidence and free this man again on the streets, selling drugs to children and smuggling weapons into your town?