With the radio mysteries, the listener only knew what the lead character told them. Television mysteries have also tried to keep the audience in the dark. This keeps the audience interested throughout the show. We must watch the whole show to find out the ending. I enjoy trying to solve the mystery before the show does and before anyone else watching the show with me can.
Many people enjoy trying to figure out a mystery.
Human nature makes us want to find out the truth. Just look at the O.J. Simpson trial. Millions of people tuned in to watch the real life mystery. We couldnt witness what happened, but everyone seemed to have their own opinions of what happened. Watching mysteries would not be nearly as exciting if we knew who committed the crime in the first place.