>> that decision to buzz them in is something rick abbot has had to live with for the past 23 years. >> the night watchman, against protocol, allowed them into the museum. >> anthony amore is the security director for the isabella stewart gardner museum. he's also an active investigator on this case. he says back in 1990, no one was allowed into the museum after hours. not even police officers. but rick, the security guard, said he'd routinely buzz in museum employees afterhours. even the museum director. >> i was never verbally told that to the best of my knowledge. i'm sure there was a policy written somewhere. but it wasn't the culture of the place, for the most part. people came in and out of there fairly regularly. at least once a month, we'd let someone in. >> so it was not unusual for rick to hear that buzzer go off.