Keith Kaneshiro said yesterday he didn't know why the Marines ultimately decided to accept guilty pleas in the May 7 murder in exchange for not charging the four defendants with a capital offense.

"They asked me to transfer jurisdiction, and I asked them to give me a reason," said Kaneshiro, a capital-punishment advocate.

"They promised they would seek the death penalty.

"I can't judge (their decision) till I talk to them. They have good reasons for doing what they have done. It was totally in their discretion."

Four Marine lance corporals pleaded guilty in the brutal, execution-style murder of Lance Cpl. Juan Guerrero, 20. Three received life in prison with possibility of parole in 10 years for premeditated murder. A fourth pleaded guilty to unpremeditated murder and received a 25-year sentence with possibility of parole in less time, defense attorneys said.

Brig. Gen. David Bice, commanding general of Kaneohe Marine Corps Base Hawaii, made the final decision to accept the plea agreements. Bice is off island, and Marine prosecutors will not talk to the media about the case.

"We would have loved to have the death penalty, but considering what (evidence) we had to go on, we probably could not have built a good capital case," said Capt. J.C. Milliman, Kaneohe spokesman. Under a capital offense, defendants cannot plead guilty.

Military investigators and defense attorneys said they thought the government's evidence was strong - early confessions from two defendants, finding Guerrero's stolen stereo equipment in the defendants' possessions, and physical evidence that Guerrero was at the scene of the beating and later in the back of the vehicle that hauled him to Nuuanu Pali Drive, where he was shot in the head.

Defense attorneys said, however, it would be extremely difficult to get a jury's unanimous decision for the death penalty.

"They were all really young men and each one had their own mitigation," said defense attorney Marine Maj. Kevin Mahne. "The defense only had to find one person sympathetic and not thinking they should die for the crime."

In that scenario, Mahne said, the defendants probably would have been convicted of second-degree murder and received life sentences - the guaranteed outcome of three of the plea agreements.

Guerrero's family as well as some Marines wanted death penalties for the killers.

"As a Marine who didn't know all the circumstances of the trial, I personally think all four should have gotten the death penalty," said Gunnery Sgt. John Diggs, Guerrero's immediate supervisor in the Communications Material Security System. Diggs also worked with three of the four defendants.

"Other Marines share that feeling," Diggs said. "Guerrero was an outstanding Marine."

No strong motive was ever established. Defendants said Lance Cpl. Michael Pereira, 22, who investigators believe instigated the murder and dominated the others, thought Guerrero had become "stuck up" and had treated him and his wife with "disrespect" after being transferred to a new job.

The other three defendants said they went along with Pereira, who lured Guerrero to his house so the group could beat him and later kill him, because Pereira was their friend.

Diggs said all of the defendants were Guerrero's platoon mates and all were candidates for the job that Guerrero eventually landed. That job had more prestige and responsibility, easier working conditions and shorter hours, especially during a platoon inspection that took place before the murder.

"There's always talk if you've got an easy assignment and somebody else has a harder one," said Diggs, adding that Guerrero had one of the highest security clearances in the military. "He couldn't talk to the guys" about his new job.

Diggs said Guerrero was concerned that two of the defendants who were about to get out of the military owed him money for stereo equipment he sold them. Diggs said most of the debt had been paid but Pereira still owed about $350.

But Diggs said "there was no indication whatsoever" that problems were serious among Guerrero and the defendants or that Guerrero was in physical danger.

Michael Moran, who led the investigation by the Naval Criminal Investigative Service, said no other motive was established, making the investigation more difficult. He praised the Honolulu Police Department, who initially handled the investigation, as well as the military for assembling such a strong case.

"It could have been circumstance-driven, personality-driven, abuse-driven, or a combination," said Moran, adding that any further motive may never be known.