By all accounts, Rigoberto Alpizar was frantic as he darted off a plane at Miami International Airport, bumping past passengers and yelling that he needed to get off the aircraft.
Some passengers say they never heard him say anything about a bomb. Federal officials say he shouted that he had a bomb in his bag, and ignored instructions to get down. When he reached for the bag, the marshals opened fire, killing him.
No bomb was found after Wednesday's shooting. Witnesses said his wife frantically shouted amid the chaos that he was bipolar, and hadn't taken his medication.
The White House and others on Thursday defended the marshals' actions, saying they appeared to have acted properly when they shot to kill the 44-year-old Costa Rican immigrant.
"The bottom line is, we're trained to shoot to stop the threat," said John Amat, national operations vice president of the Federal Law Enforcement Officers Association and a deputy with the U.S. Marshals Service in Miami.
"Hollywood has this perception that we are such marksmen we can shoot an arm or leg with accuracy. We can't," Amat said. "These guys were in a very tense situation. In their minds they had to believe this person was an imminent threat to themselves or the people on the plane."
Both air marshals were hired in 2002 from other federal law enforcement agencies and are now on administrative leave, said Homeland Security spokesman Brian Doyle. Miami-Dade police were investigating and the medical examiner's office was performing an autopsy.
"He was belligerent. He threatened that he had a bomb in his backpack," Doyle said. "The officers clearly identified themselves and yelled at him to 'get down, get down.' Instead, he made a move toward the backpack."
It wasn't clear where in Alpizar's frantic dash officials say the marshals heard the threat. At least two passengers on the Orlando-bound flight said they didn't hear Alpizar mention a bomb.
"I absolutely never heard the word 'bomb' at all," said John McAlhany, who was returning from a Key West fishing trip. "I never heard the word 'bomb' when we got off the plane. I never heard the word 'bomb' when we were sequestered. The first time I heard the word 'bomb' was when I was interviewed by the FBI."
Added another passenger, Mary Gardner: "I did not hear him say that he had a bomb."
Alpizar appeared agitated before boarding the plane and was singing "Go Down Moses" as his wife tried to calm him, said passenger Alan Tirpak.
"The wife was telling him, 'Calm down. Let other people get on the plane. It will be all right,'" Tirpak said. "I thought maybe he's afraid of flying."
McAlhany recounted how, once aboard, Alpizar told his wife, "I've got to get off the plane," then bumped passengers and flight attendants on his way down the aisle.
"When he got to the first-class cabin, the marshals jumped up," McAlhany said. "After that, it was on the jetway. Only those two air marshals and God know what happened."
Alpizar's wife, Anne Buechner, had tried to explain he was bipolar, a mental illness also known as manic-depression, and was off his medication, witnesses said. The National Alliance on Mental Illness called on the Air Marshal Service and other law enforcement agencies to train officers in responding to people with severe mental illness.
But whether Alpizar was mentally ill didn't matter while marshals were trying to determine if the threat was real, others said.
"The person was screaming, saying he would blow up the plane, reaching into his bag - they had to react," Amat said.
Mental illness can make a situation more volatile, said Jim Pasco, executive director of the National Fraternal Order of Police.
"What if the officer had said, 'I think this guy is full of it, I don't think he has anything,' and that plane had been blown to smithereens," Pasco said. "What would the second guessers be saying then?"