Tatum, of Edmond, Okla., was facing involuntary manslaughter, reckless endangerment and aggravated assault charges related to the deaths of 24 Iraqis, including 11 women and children.

The military said the move was to allow "the truth seeking process" to continue. Tatum is now free to testify as a neutral witness in Wuterich's trial.

But it also means Wuterich, a staff sergeant and the squad leader, is the only man who was in Haditha that day still facing a military trial.

Wuterich, a 1998 Platt High School graduate, was first charged with 18 murder counts in 2006, but a military judge reduced it to nine counts of voluntary manslaughter after his military grand jury hearing last year.

Wuterich also is charged with aggravated assault, reckless endangerment, dereliction of duty and obstruction of justice.

The charges carry a combined maximum sentence of 160 years in prison, but experts have said it's unlikely he would receive such a punishment.

The dismissal of Tatum's case was unexpected, said Neal A. Puckett, one of Wuterich's attorneys.

Tatum had been given immunity to testify in Wuterich's trial, which was delayed indefinitely earlier this month because of another lawsuit.

Puckett said it could have been too difficult to try Tatum since some of his statements were admissible only in Wuterich's trial.

Still, the immunity is "extremely significant," Puckett said Friday. The military has offered full exoneration to three of the men who fired weapons in Haditha in hopes that their testimony will help the prosecution.

Prosecutors also are suing CBS News to release unaired portions of an interview Wuterich did last year with "60 Minutes." That matter has delayed his trial.

"All these things thrown into the case at the same time ... it's a complete act of desperation by the government to salvage its case against Frank," Puckett said.

Although Tatum and other Marines made statements to Navy investigators that helped the military level charges against Wuterich, Puckett said the Naval Criminal Investigative Service "is world famous for deciding very early on what happened and trying very early on to get evidence" to support that.

"That's going to be revealed as the fundamental flaw in this case."

Also in Wuterich's favor is that Haditha was his first experience in combat.

"That's going to be huge," said Puckett, a former military judge. "That looms large."

Wuterich's mother, Rosemarie, said Frank was "glad that this is over for Stephen," but "there's kind of mixed feelings here. He says he's the last man standing."

Wuterich has been on limited duty at Camp Pendleton in Southern California since news of the Haditha incident broke two years ago. He lives with his wife Marisol and their three daughters, ages 8, 6 and 14 months.

His parents, who live on Meriden's west side, are anxious for the trial to take place and the matter to be put to rest.

"As far as I'm concerned, they don't have anything credible and anything they can prove," Rosemarie Wuterich said. "I'm so glad for (Tatum) and his family. I just hope that it keeps on going that way."

Two officers also are facing trial for failing to investigate or obstructing the investigation of the Haditha incident.

Money has continued to pour in for Wuterich's legal defense fund, Rosemarie Wuterich said.