GTA V - A Mystery, Solved

There is a total of 50 letter scraps in hidden locations along San Andreas. The letters are basically just little papers, and when you are near by, you will hear a paper like sounds flowing in the wind. There is no way to check how many you have collected, or if you have missed any. So make sure you follow to the locations one by one, and obviously avoid missing any.
Once you have collected all of the letter scraps, you will switch to the character 'Franklin'. After you are switched, go to the "?", that will be located at the Golf Course. When you are there you will meet a murderer, you will then go on a chase. And while you are on this chase you will need to shoot whenever possible, and complete the mission. This will unlock A Mystery, Solved. And you're done.