Investigators are trying to determine if a fire alarm sensor was up to date and working after it sent staffers to an area with no fire. More than 20 minutes later a second alarm went off and the fire department was called.
About NBC Nightly News with Lester Holt
Watch "NBC Nightly News with Lester Holt," providing reports and analysis of the day's most newsworthy national and international events. See More
Check out more stuff on Yahoo View