Authorities say they're investigating the cause of a fire at the apartment of a man accused of gunning down a security guard at a federal building in Las Vegas.
Authorities say a U.S. marshal was wounded in the firefight before the gunman was shot to death Monday morning.
Two law enforcement officials say the gunman was upset over losing a lawsuit about his Social Security benefits. In a 2008 lawsuit, Johnny Lee Wicks complained about a cut in his benefits and accused federal workers of discriminating against him because he's black.
Authorities say the fire at the seniors complex damaged Wicks' apartment. A neighbor there described him as a quite man who lived alone.
Democratic Senate Majority Leader Harry Reid says one of his aides was in the atrium as the shooting began. He says she had bent over to pick up some newspapers as the gunman opened fire and believes that saved her life.