CAMP PENDLETON, Calif. — The mother of a Kane'ohe Bay Marine who witnesses say covered a grenade with his body to save comrades in Iraq plans to appeal to Congress to award her son the nation's highest military honor after learning it was denied by Defense Secretary Robert Gates because of questions about his final act.

Rosa Peralta said Thursday she made the decision after a Marine general told her that her son, Sgt. Rafael Peralta, would be awarded the Navy Cross rather than the Medal of Honor because the nomination was tainted by reports he was accidentally shot by a fellow Marine shortly before an insurgent lobbed the grenade.

"I'm going to see what can be done, because I'm not satisfied with what they want to do now," she said in Spanish.

President Bush singled out the Marine's actions in a 2005 Memorial Day speech, saying Peralta "understood that America faces dangerous enemies, and he knew the sacrifices required to defeat them."

"The president spoke of him. So how is this now possible that they do this," Rosa Peralta said.

She said she was considering rejecting the Navy Cross, the second-highest award for valor in combat that can be awarded to a Marine. Peralta, who had been based at Kane'ohe Bay before being deployed to Iraq, will be the 24th recipient of the Navy Cross for actions in Iraq and Afghanistan.

"I still don't know what I'm going to do," she said.

The question about whether to award Peralta the Medal of Honor centers on whether the mortally wounded Marine, who was shot in the head and upper body, could have intentionally reached for the grenade and covered it with his body.

"There was conflicting evidence in the case of Sgt. Peralta as to whether he could have performed his final acts given the nature of his injuries," said Capt. Beci Brenton, spokeswoman for Navy Secretary Donald Winter.

The initial recommendation that he receive the Medal of Honor went through reviews by the Marine Corps, U.S. Central Command, the Department of the Navy and ultimately up to Defense Secretary Gates, Brenton said.

After all the evidence was scrutinized, officials determined that it "did not meet the exact standard necessary to support the Medal of Honor," she said.

But Rosa Peralta said she was led to believe her son would get the Medal of Honor in a November 2007 telephone call from an undersecretary of the Navy, who she says told her the nomination was to be forwarded to the White House.

Defense Department spokesman Bryan Whitman said there was a June 2007 Navy recommendation for the Medal of Honor, but it never went to the White House because Gates didn't approve it.

He said that because there was some contradictory evidence, Gates instead took the extra step of asking five other individuals to review the case — a former commander of U.S. forces in Iraq, a Medal of Honor recipient, a civilian neurosurgeon who is retired from the military and two forensic pathologists who also are military retirees.

The five were given medical reports that had not been available in the initial review. They thoroughly reviewed the case again, including inspecting the evidence and re-enacting the event, Whitman said.

"Each independently recommended to the secretary that the evidence did not support the award of Medal of Honor," he said.

Gates made his decision this month.

Peralta was shot several times in the face and body during a house-to-house search in Fallujah on Nov. 15, 2004, during some of the fiercest fighting of the war.

According to witness accounts, Peralta lay mortally wounded on the floor of a house and grabbed a grenade lobbed by fleeing insurgents. His body absorbed the blast and he died immediately.

In a rare move, the Marine Corps Thursday released a redacted copy of the Medal of Honor nomination by Lt. Gen. Richard Natonski and an investigative report detailing the "friendly fire" shooting of the sergeant.

The report found sufficient evidence existed to believe that Peralta was probably shot by a fellow Marine and that a gunshot wound to the head and injuries to the head from a grenade caused his death.

The nomination, which relies on witness statements, forensics, bomb fragment analysis and an autopsy, concluded that although Peralta was shot in the head, he made "a conscious, heroic decision to cover the grenade and minimize the effects he knew it would have on the rest of his Marine team."

The nomination details Peralta's actions in the final minutes of his life, with several witnesses recounting how the Marine lay face down and used his arm to pull the grenade to him. It also says a forensic analysis of Peralta's clothing and flak jacket show the grenade was underneath him when it exploded.

Peralta, who was assigned to Hawai'i's 1st Battalion, 3rd Marine Regiment, moved to San Diego from Tijuana as a teenager. He was 25.

Associated Press writers Pauline Jelinek in Washington, D.C., and Thomas Watkins in Los Angeles contributed to this report.