An Army officer was sentenced to 25 years in prison by a military jury Saturday for shooting and killing an Iraqi detainee during an interrogation. First Lt. Michael Behenna was convicted a day earlier of murder and assault, but acquitted of making a false statement. He had faced up to life in prison. "We are disappointed at the jury's verdict and the sentence," Behenna's attorney Jack Zimmermann said. Zimmermann said he has filed a motion for a mistrial, claiming prosecutors withheld evidence that could help Behenna's defense. The judge has scheduled arguments on the motion Monday, Zimmermann said. Behenna testified he was trying to defend himself when he shot Ali Mansour Mohammed and that the detainee reached for the officer's gun in a secluded railroad culvert near Beiji, Iraq, in May. Prosecutors said the detainee was defenseless against Behenna and the officer's threats and other actions showed he had planned to kill the man. Zimmermann said Behenna wouldn't have brought along an Iraqi translator if he had planned to kill the detainee. Behenna testified that he threatened Mohammed and pointed his gun at him to scare out information about a roadside bombing that killed two members of his platoon. Behenna said he believed Mohammed was involved in the bombing and could provide names of the insurgents responsible. After the detainee was shot twice, once in the head and once in the chest, another Fort Campbell soldier testified that he tossed an incendiary grenade on the body. Staff Sgt. Hal Warner, pleaded guilty this month to charges of assault, maltreatment of a subordinate and making a false statement. Warner, from Braggs, Okla., was sentenced to 17 months in prison and testified against Behenna. As part of his sentence, Behenna received a dismissal and forfeiture of pay and allowances, said 101st Airborne Division spokesman Maj. Johnpaul Arnold.