Col. James L. Pohl, a military judge acting as the investigating officer in the case, said that keeping the hearing open would preserve the integrity of the military justice system. He previously said he planned to call the 32 people injured in the attack to testify during next month's Article 32 hearing, the military equivalent to grand jury proceedings.
Complete Coverage: Tragedy at Fort Hood
John Galligan, an attorney for defendant Maj. Nidal Hasan, sought to keep the hearing closed, saying allowing the public to hear the testimony from nearly three dozen witnesses would create so much pretrial publicity that it would make it impossible for his client to get a fair trial.
Hasan, an Army psychiatrist, is charged with 13 counts of premeditated murder and 32 counts of attempted premeditated murder in the Nov. 5 shootings at the Texas Army post. Military prosecutors have not said whether they would seek the death penalty.
Pohl also denied a defense request to exclude autopsy reports from being presented at the Oct. 12 hearing.
Lt. Col. Kris Poppe, a defense attorney, said testimony about the autopsy reports might touch on bullet trajectory and how long it took the victims to die, but that the defense had been denied a request for its own expert to independently review the reports.
Military prosecutors said they would only use autopsy reports to show the 13 victims died of gunshot wounds.
Thursday's hearing was Hasan's second appearance in a Fort Hood courtroom. He never spoke during the hearing as he sat in a wheelchair, wearing his Army combat uniform and a knit cap that he pulled over his ears at times.
Hasan, who was paralyzed from the chest down after being shot by two Fort Hood police officers, was treated at a San Antonio military hospital until his April transfer to the Bell County Jail, which houses military suspects for nearby Fort Hood. The military justice system does not have bail for defendants.