The trial of an army officer charged with killing 13 people at Texas army post starts Tuesday, a rare and complicated US military death penalty case that has faced numerous delays since the massacre nearly four years ago.
Maj. Nidal Malik Hasan doesn't deny that he carried out the November 2009 rampage at Fort Hood, one of the worst mass shootings in US history. There are dozens of witnesses who saw it happen. Military law prohibits him from entering a guilty plea because authorities are seeking the death penalty.
Although the Hasan case is unusually complex, experts also say the military justice system is unaccustomed to dealing with death penalty cases and has struggled to avoid overturned sentences.
No active-duty US soldier has been executed since 1961. If Hasan is convicted and sentenced to death there are likely years, if not decades, of appeals ahead. He may never make it to the death chamber at all.
The attack occurred in a building where hundreds of unarmed soldiers, some about to deploy to Afghanistan, were waiting for vaccines and routine checkups.
Hasan walked inside with two handguns, climbed onto a desk and shouted "Allahu Akbar!" an Arabic phrase meaning "God is great!" Then he fired, pausing only to reload.
A reversed verdict or sentence on appeal in the Hasan case would be a fiasco for prosecutors and the Army. That's one reason why prosecutors and the military judge have been deliberate leading up to trial, said Geoffrey Corn, a professor at the South Texas College of Law and former military lawyer.
"The public looks and says, 'This is an obviously guilty defendant. What's so hard about this?'" Corn said. "What seems so simple is in fact relatively complicated."
Hasan is charged with 13 specifications of premeditated murder and 32 specifications of attempted premeditated murder.
More than 30 people were wounded in the shooting.
Thirteen officers from around the country who hold Hasan's rank or higher will serve on the jury for a trial that will likely last one month and probably longer. They must be unanimous to convict Hasan of murder and sentence him to death. Three-quarters of the panel must vote for an attempted murder conviction.
