Los Angeles (CNN) -- The suspected Los Angeles International Airport gunman walked up to a security checkpoint, shot a TSA officer "at point-blank range," went up an escalator, then came back down to shoot his victim again, a federal prosecutor said Saturday. That TSA officer, Gerardo Hernandez, died of his wounds. The man who shot him, authorities say, is 23-year-old Paul Anthony Ciancia. A federal complaint was filed Saturday afternoon charging Ciancia with two felony offenses -- murder of a federal officer and commission of violence in an international airport, said U.S. Attorney Andre Birotte Jr.. If convicted, Ciancia would face life in prison without parole or the death penalty, according to the federal prosecutor. The U.S. attorney general would decide if a death sentence would be sought.
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NEW: Prosecutor: The suspect shot TSA officer, went away, came back, shot officer again
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He wrote that he wanted to "instill fear" in TSA employees, FBI official says
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FBI: 5 people total were shot, including 3 TSA officers and a civilian
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The suspect is "unresponsive," hasn't answered questions, FBI official adds
In his diatribe, the gunman claimed the TSA treats @placeholder like terrorists even though all people aren't equally dangerous, a U.S. law enforcement official said.
@placeholder's family became concerned in recent days after he sent his brother and father "angry, rambling" texts venting about the government, living in Los Angeles and his unhappiness generally, an intelligence source said.