(CNN) -- Attorneys argued again Thursday about whether accused Fort Hood shooter Maj. Nidal Hasan can be forcibly shaved so that his stalled court-martial can proceed.
Thursday afternoon's hearing at the Army Court of Criminal Appeals in Virginia was called to address Hasan's continued refusal to shave before court appearances, the Army said.
Seven appellate judges listened to the oral arguments for more than an hour, but did not decide on this issue.
The military psychiatrist is accused of opening fire three years ago at the Texas Army post's processing center, where soldiers were preparing to deploy to Afghanistan and Iraq.
The attack left 13 dead and 32 people wounded. Hasan was paralyzed from the waist down after police exchanged fire with him.
His court-martial tied to the shooting had been scheduled to start in August. But the appeals court had delayed its start indefinitely to determine whether the suspect's beard can be forcibly shaved during trial.
Army regulations prevent soldiers from wearing facial hair while in uniform. Hasan, who is still considered a soldier, is a practicing Muslim and maintains he has the right to wear the beard under U.S. laws protecting religious freedoms.
At an earlier hearing in August, Hasan spoke about the bushy beard he had grown.
"Your honor, in the name of almighty Allah, I am a Muslim. I believe that my religion requires me to wear a beard," he told the judge, Col. Gregory Gross.
Prosecutors argued that Hasan should have to shave his beard, saying having it long would make it harder for witnesses to identify him as the shooter in court.
Gross ordered that Hasan would have to shave, triggering the appeal from Hasan's lawyers that was argued Thursday.
After the court rules, the decision can be appealed again to the U.S. Court of Appeals for the Armed Forces, an independent tribunal with worldwide jurisdiction over active-duty members of the U.S. armed forces and others subject to the Uniform Code of Military Justice.
If convicted of the shooting, Hasan can be sentenced to death.
A U.S.-born citizen of Palestinian descent, he was a licensed psychiatrist who joined the Army in 1997. He had been scheduled to deploy to Afghanistan before the killings in November 2009, but had been telling his family since 2001 that he wanted to get out of the military.
Hasan had told his family he had been taunted after the terrorist attacks of September 11, 2001. Investigations tied to the Fort Hood shootings found he had been communicating via e-mail with Anwar al-Awlaki, a prominent radical Yemeni-American cleric killed by a U.S. drone attack in 2011.