in history. >> come in. clock in. there would be two guards. >> reporter: rick abath was one of the night watchmen on duty the night of the crime. until now, he'd never done a television interview about what happened that night. rick was 23 years old back in 1990. he had been working at the museum for about a year. the guard shift began at 11:30 p.m. a shift that most nights was uneventful. >> bored. sit around, walk around basically. one guy would go up and start his round, and then when he came back the other would get behind the desk and the other person would go up. >> reporter: on this night, things would be far from boring. during the night shift, there is always one guard man ng tning t security desk by the side door -- the employee entrance