Among the 83 claimants are relatives of eight soldiers killed, and nine soldiers and one civilian who were injured when army psychiatrist Major Nidal Hasan opened fire at at the Fort Hood military post in Texas on November 5, 2009.
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They accuse the Defense Department, the Justice Department and the FBI of willful negligence in failing to prevent the attack, which killed 13 people and wounded 31 others.
According to the claims, filed last week, the government had clear warnings that Hasan was a serious threat to the lives of others, but chose to allow him to continue serving on active duty. Hasan was promoted to major just five months before carrying out the massacre.
The lawyer representing the claimants, Neil M. Sher, told Reuters:
"The Army knew all about his beliefs, his radicalization, and, even knowing that, his superiors did absolutely nothing except promote him. That is inexcusable."
Fort Hood officials refused to comment on the claims, the AP said.
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A Senate report in February concluded that Hasan's superiors failed to discipline or investigate him despite his repeated discussion of Islamist extremism and suicide bombings, and his reputation among colleagues as a "ticking time bomb."
Hasan is due to face a court martial in March on 13 counts of premeditated murder and 32 counts of attempted premeditated murder. He faces the death penalty or life imprisonment without parole.
Nine Army officers were reprimanded for failing to act, USA Today said.
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