Postcognition is the ability to see past events using your psychic sense. A psychic detective who helps the police solve crimes are most commonly to use this ability along side psychomentry. This ability is the opposite to precognition. A technique of training this is: Pick an unfamiliar picture. Use remote viewing to know the full surroundings of where the picture was taken and then repeat the event as if it was a recorder video tape.
Like precognition, postcognition can sometimes just happen unexpected. Like you're alone or in a quiet room and suddenly you get visions of a car crash which happen about a day ago or you may get a vision of a brutal murder or anything really.