Fort Hood shooting suspect Maj. Nidal Malik Hasan was formally charged in military court Thursday with 13 counts of premeditated murder.
Maj. Hasan, 39, remained hospitalized with gunshot injuries he received from two civilian police officers credited with stopping the massacre that left 13 dead and 29 wounded.
Army Criminal Investigation Division spokesman Chris Grey said during a brief news conference at the Texas base that the investigation is ongoing and more charges are possible. He did not take questions from reporters.
"These are initial charges and additional charges may be in the future," he said. "This is the first step in the court marshal process."
Mr. Grey also attempted to address the controversy about who struck down Maj. Hasan as he fired more than 100 rounds from a semi-automatic handgun.
Reports immediately after the Nov. 5 shootings said Sgt. Kimberly D. Munley, a civilian police officer, arrived several minutes after the shootings started at about 1:30 p.m. inside a post assignment-processing center.
Witnesses later said a second civilian police officer, Sgt. Mark Todd, arrived in a separate vehicle and helped Sgt. Munley, who fell to the ground after being shot four times — once in the wrist and three times in the legs.
Mr. Grey said they both participated in stopping Maj. Hasan but provided no specific details.
"I would caution anybody from making conclusions … until all the evidence has been process," said Mr. Grey, who described the crime scene as complicated.
Sgts. Munley and Todd appeared together Wednesday on the "Oprah Winfrey Show" and said they both helped in stopping Maj. Hasan. Sgt. Todd also said he kicked the gun away from Maj. Hasan, then put him in handcuffs.
Seperately Thursday, President Obama announced that he ordered that all intelligence files related to the case be reviewed to determine how various agencies gathered, shared and acted upon information learned about Maj. Hasan before the shooting.
The order was made amid questions about whether authorities missed troublesome signs before the deadly rampage.
An FBI-led Joint Terrorism Task Force knew that Maj. Hasan had extensive contacts with a radical Imam located in Yemen, but did not pursue an investigation because the substance of the conversations were not considered to be related to threats or potential violence.
The Washington Times has also learned from two U.S. officials that Maj. Hasan had contact with numerous other Muslim extremists, including some under federal investigation and who have links to al Qaeda.
• Staff writer Joseph Weber contributed to this story.