I just found this on the BBC – Broadcasting and Cable Blog:

If you watched cable news networks covering the bomb scare at Miami International Airport this afternoon, you got a lot of conflicting information. In the 24/7 news world, muddy details are okay, as long as they’re explained that way, and Fox, CNN and MSNBC certainly did that.
It was fascinating as reporters strung together nuggets of information about what happened. MSNBC seemed to be the luckiest. A passenger, Mary Gardner, called the NBC-owned WTVJ Miami and gave a remarkably professional report from a bus where the passengers were sent after the incident was over. (If she’s not a reporter, then she should be.)
Gardner described how an “English-speaking, blonde-haired woman, probably late 30s, early 40s” earlier was in the front of the plane speaking frantically on a cellphone before joining her husband near the rear of the plane. Then shortly before takeoff, her husband began “running crazily” from the back of the plane toward the front as Miami passengers were boarding. Gardner said his wife was running after him, exclaiming, “My husband! My husband!”
Later, it was reported, his wife tried to tell air marshals that the fellow was bi-polar and off his medication. (He was a 44-year-old American, it was announced earlier. At about 5 p.m., officials identified him as Rigoberto Alpizar.) Gardner didn’t hear him shouting that he had a bomb, but apparently he did.
Gardner had the good fortune to be sitting next to a retired pilot, who pointed out the air marshals getting into position. After a pursuit, four or five shots were fired, she said.
MSNBC and WTVJ reported he was dead by at least 3:22.No one seemed to have good information, even a couple of hours later, on if this guy had a bomb or not. But by about 4:45 it was reported that Alpizar, though still not named at that point, did not have a bomb.
A lot of other things were confusing. American Airlines Flight 924 was coming from Medellin, Colombia, stopping over in Miami and continuing to Orlando. It wasn’t immediately known if the couple was coming from Colombia or joining the flight in Miami. MSNBC, CNN and Fox did admirable reporting assembling the facts; CNN reported “another network” was reporting the suspect was dead. Fox, from what I could tell, reported that he was reportedly dead.
The reason why he was shot was a little muddy. There were some reports that he stopped when the air marshals told him to but then grabbed for his carry-on bag. Other reports said he didn’t stop but grabbed for his bag. That’s when he was shot.
Gardner didn’t know for sure if he was shot on the plane, but she thought it might have happened in first class. Later, it was reported that he was shot in the airway, the contraption that connects the airliner to the terminal.