air marshalls

I found the story about the bi-polar man who was shot to death by a federal air marshall because he claimed to have a bomb very disturbing today. I realize and fully understand that these individuals are there to protect passengers, however, I cannot help but wonder if there are certain regulations that guide their actions in such circumstances... are they supposed to fire at anyone who claims they have a bomb? do they attempt to debilitate the person by shooting at his feet or any other location that might not be immediately fatal? I can only judge the situation based on what I am hearing from the news, and it's probably a much different situation when you are in charge of security and some man runs around saying he has a bomb. However, even this claim has not been independently corroborated by other passengers... they said his wife was running after him saying that he needed medication and was mentally ill. Should the marshalls have listened to her and risk that this could be some sort of fake scenario? But then again, assuming that they were terrorists who really had bombs, why would they act out something like that? I would assume they would just blow themselves up, without warning.

A "routine" investigation is being conducted, the White House said today. This even should be an eye opener for air marshalls and their trainers. A similar situation occurred in the summer when British police forces shot and killed a Brazilian man in the subway system after the 7/11 attacks in London. When this involves the loss of an innocent and sick man's life, I believe more than a "routine" investigation should be conducted, and one that is independent of government influence.