Maj. Nidal Hasan is charged with 13 counts of premeditated murder and 32 counts of attempted premeditated murder in the November 2009 shooting spree at the Texas Army post.
It was not immediately clear when Hasan will be arraigned in a Fort Hood courtroom. He must plead not guilty based on the nature of the case, according to military law.
Hasan's lead attorney, John Galligan, had urged the commanding general not to seek the death penalty, saying such cases were more costly, time-consuming and restrictive. In cases where death is not a punishment option for military jurors, soldiers convicted of capital murder are automatically sentenced to life imprisonment without parole.
"I believe the Army as an institution has long been planning to go this route," Galligan told The Associated Press on Wednesday from his office near Fort Hood, about 125 miles south of Fort Worth.
Two Army colonels who reviewed the case previously recommended that Hasan be tried in a military court and face the death penalty.
Galligan has declined to say whether he is considering an insanity defense for his client. He has refused to disclose results of a military mental health panel's evaluation of Hasan but said it would not prevent the military from pursuing a court-martial.
The three-member panel determined whether Hasan is competent to stand trial and his mental state during the shootings. It also determined if he had a severe mental illness that day, and if so, whether such a condition prevented him from knowing at the time that his alleged actions were wrong.
Hasan was paralyzed from the waist down after being shot by police the day of the rampage. He remains jailed in the Bell County Jail, which houses defendants for nearby Fort Hood.
Hasan has attended several brief court hearings and an evidentiary hearing last fall that lasted about two weeks. He sometimes took notes and showed no reaction as 56 witnesses testified, including more than two dozen soldiers who survived gunshot wounds.
Witnesses testified that a gunman wearing an Army combat uniform shouted "Allahu Akbar!" -- which is Arabic for "God is great!" -- and started shooting in a small but crowded medical building where deploying soldiers get vaccines and other tests. The gunman fired rapidly, pausing only to reload, even shooting some people as they hid under tables or fled the building, witnesses said. He fatally shot two people who tried to stop him by throwing chairs, and killed three soldiers who were protecting civilian nurses, according to testimony.
The gunman was identified as Hasan, an American-born Muslim who was scheduled to deploy to Afghanistan the following month. Before the attack, Hasan bought a laser-equipped semiautomatic handgun and repeatedly visited a firing range, where he honed his skills by shooting at the heads on silhouette targets, witnesses testified during the hearing.