By Jim Forsyth
SAN ANTONIO (Reuters) - Accused Fort Hood gunman, Army psychiatrist Nidal Hasan, was due in court Tuesday for a hearing that could be key in determining whether he will face the death penalty for the murders of 13 people during a shooting rampage at the military post in November 2009.
Military judge Colonel Tara Osborn is expected to rule on whether prosecutors can solicit testimony from terrorism expert Evan Kohlmann, who has testified at the trials of a number of al Qaeda-linked suspects.
Prosecutors are hoping to establish that the deadly rampage was premeditated, proof of which is essential under the Uniform Code of Military Justice. Premeditated murder carries a potential death penalty.
"This witness is expected to testify that Hasan was on extremist web sites and that he was receiving information that was motivating him into engaging in acts of deadly violence against United States interests," said Geoffrey Corn, a professor at the South Texas College of Law and former senior attorney in the Army's Judge Advocate General's office.
If jurors do not find Major Hasan guilty of premeditated murder, Corn said, they could still convict him on charges of second-degree murder, for which he could not be sentenced to death.
Kohlmann's testimony is likely to show that Hasan's mental was rational and that there was evidence the crimes were planned, said Richard Rosen, an expert on military law at Texas Tech University.
"The witness will establish motive, which will assist in proving premeditation," Rosen said. Hasan "appears to have been motivated by Islamic extremism and clearly wanted to attack the United States."
The defense team - which Fort Hood has not made available for interviews - is likely hoping the government will commit an error that will cause the case to be thrown out or for the punishment to be downgraded, said Jeffrey Addicott, a retired Army Lieutenant Colonel who heads the Center for Terrorism Studies at St. Mary's University in San Antonio.
"The defense will contest every issue and witness," Addicott said.
Opening arguments in Hasan's court martial are expected to begin in July with the choosing of the jury set to begin in late May.
(Editing by Corrie MacLaggan and Gunna Dickson)