MARINE CORPS BASE CAMP PENDLETON, Calif. -- A military jury declared Gunnery Sgt. Archie O'Neil guilty of premeditated murder Friday -- but couldn't agree to give him the "mandatory minimum" sentence. So they came up with their own -- prompting judge Col. Robert Chester to declare a mistrial in the sentencing phase Monday. Legal team members from both sides say the mistrial doesn't throw out the guilty verdict -- although O'Neil's exact fate is up in the air indefinitely. The jury declared O'Neil guilty after 2-1/2 weeks of hearing evidence. The panel of three senior-enlisted Marines (all men) and four officers (three men and one woman) deliberated for less than a day before finding O'Neil guilty on all charges -- including adultery, carrying a concealed weapon, failure to obey a general order and failure to obey a base order.The convictions meant at least two-thirds of the jury deemed O'Neil guilty. The actual count was not disclosed. However, during sentencing Monday, the jury deadlocked. Conviction for premeditated murder gives the jury two possible choices -- life in prison with or without parole. They gave him neither.Three-fourths of the jury must agree on a sentence in this type of court martial. "The majority of the members didn't believe (either) was appropriate," said Maj. Leon Francis, co-counsel for the defense. "They gave him a term of years."Since a term of years doesn't fit the mandatory minimum sentence, Chester rejected their recommendations, Francis said. "None us of us has heard of this before," Francis said, referring to other lawyers involved in the case. "There is only one situation in law this can happen -- and (premeditated murder) is it." Lt. Col. Paul Boughman, director of the base's Legal Services Support Section, agreed the mistrial is "very unusual." It's something he hasn't seen in 17 years of serving as a military staff judge advocate. "We haven't had many murder cases on base," he said.Boughman speculated a majority of jurors, under the mandatory minimum sentence mandate, thought "one sentence was too harsh, one was not harsh enough." If given a life sentence with parole, O'Neil would have been eligible for a parole hearing in 20 years. According to a prosecution legal team member, a new jury will be selected and will listen to audiotapes from the case. From those tapes, they'll try to arrive at an allowable sentence. The team member said he didn't know when a new jury would be impaneled. The body of the victim, Kimberly O'Neal (no relation to O'Neil), was found Feb. 29, 2004, in Deer Park near Camp Horno. She'd been shot 11 times with a .45-caliber pistol, crime investigators said. O'Neil left the next morning with his unit to Kuwait, where prosecutors contend he disposed of the murder weapon. O'Neil was arrested the same day and later confessed to the shooting. But O'Neil pleaded not guilty. Defense lawyers argued he suffered from post-traumatic stress disorder and a troubled childhood. After an alleged threat from O'Neal to kill his family, the defense said, O'Neil snapped and shot O'Neal. Although the defense did not dispute the defendant killed O'Neal, they stated the murder was fueled by passion and not premeditated. A conviction for premeditation in a court-martial brings the heaviest sentence possible for murder.