Airport security members divert traffic around the Marriott before getting to Terminal B at Bush Intercontinental Airport on Thursday, May 2, 2013 in Houston. Shots were fired near a ticket counter, critically injuring one armed man and sending people in the terminal scrambling and screaming, a Houston police spokesman and witnesses said. One person has been taken to an area hospital with life threatening injuries. It was not immediately clear who fired the shots. (AP Photo/Houston Chronicle, Karen Warren ) MANDATORY CREDIT

Associated Press
Airport security members divert traffic around the Marriott before getting to Terminal B at Bush Intercontinental Airport on Thursday, May 2, 2013 in Houston.   Shots were fired near a ticket counter, critically injuring one armed man and sending people in the terminal scrambling and screaming, a Houston police spokesman and witnesses said.   One person has been taken to an area hospital with life threatening injuries. It was not immediately clear who fired the shots.  (AP Photo/Houston Chronicle, Karen Warren ) MANDATORY CREDIT
Airport security members divert traffic around the Marriott before getting to Terminal B at Bush Intercontinental Airport on Thursday, May 2, 2013 in Houston. Shots were fired near a ticket counter, critically injuring one armed man and sending people in the terminal scrambling and screaming, a Houston police spokesman and witnesses said. One person has been taken to an area hospital with life threatening injuries. It was not immediately clear who fired the shots. (AP Photo/Houston Chronicle, Karen Warren ) MANDATORY CREDIT