Forensic Files is a fascinating show. Each episode is 22-minutes long, centers on an actual serious crime, and there's a solution at the end.
Law enforcement officials actually watch this show, even in a couple of cases they admitted solving a crime based on information they learned during the show. It can't get any better than that.
Occasionally the episode is about a mysterious illness that affected a town, but there's always a resolution at the end.
The narrator has this cool voice and he speaks with a well-balanced tone without much dramatization, which makes it more appealing.