A little more from the original link to the UAL flight story:
The flight attendants now began closely monitoring what the men were doing. One of the men carried a hand-held mirror as he walked around the plane. According to one flight attendant, the man "was holding [the mirror] and moving it around so he could see what was going on behind him. What he was doing was very suspicious."
Another flight attendant noted that the men had electronic gadgets with them. "They were not Game Boys or computers," said the veteran crew member, "but small electronic devices. I didn't recognize what they were." Other flight attendants took notice of the electronic equipment as well -- some of which was being passed among the men. "They started passing this one electronic device back and forth," said another flight attendant. "It looked like a transistor radio, only it wasn't."
KIRKSVILLE, Mo. (AP) — The Federal Aviation Administration says a commuter jet has crashed in northeastern Missouri, killing at least five people.