The Army psychiatrist is charged with 13 counts of premeditated murder and 32 counts of attempted premeditated murder in the Nov. 5 shooting. Premeditated murder carries the death penalty.
But if military jurors convict Hasan, they can only sentence him to death if they determine there is an aggravating factor in the case, according to military law.
Defense attorney John Galligan said the notice he received from prosecutors outlines as an aggravating factor that more than one person was killed in the same incident.
"They've done everything except tell me to my face that they plan to seek the death penalty," Galligan told The Associated Press from his office near Fort Hood, about 130 miles southwest of Fort Worth.
Military prosecutors have not publicly said what punishment they plan to seek, and Fort Hood officials did not immediately return calls seeking comment Wednesday.
Richard Stevens, an attorney who defends military cases and is not involved in Hasan's case, said crimes that are ineligible for the death penalty do not require jurors to consider aggravating factors.
"The only reason to send a notice of aggravating factors is if you're trying to seek the death penalty," Stevens said.
Military law allows for about a dozen possible aggravating factors, but prosecutors listed only one in the notice to Hasan's attorney.
Stevens said the notice indicates prosecutors plan to present evidence about aggravating factors at Hasan's Article 32 hearing, which is similar to a grand jury proceeding. The hearing, after which a military judge will determine whether there is enough evidence to go to trial, could be held as early as July 1.
The commanding general over Hasan's unit ultimately will determine if prosecutors can seek the death penalty, Stevens said.
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