Menchaca and Tucker disappeared Friday during an attack on a checkpoint south of Baghdad, in which another GI was killed.
Iraqi officials said Tuesday the Americans were first tortured and then killed in a "barbaric" way. According to a web statement that has not been authenticated, the terror group Al Qaeda in Iraq is claiming it killed the U.S. soldiers. The statement also says the soldiers were "slaughtered" by the new head of the group, successor to Abu Musab al-Zarqawi, who was killed by a U.S. air strike on June 7th.
The language in the statement suggests the men were beheaded.
U.S. Maj. Gen. William Caldwell says the cause of death for the bodies found Monday and recovered Tuesday is "undeterminable at this point."
Caldwell declined to comment on the condition of the bodies or specify whether they had been killed in the attack on Friday or were in fact kidnapped and killed later, saying only that they were found together in the vicinity of an electrical plant.
"Based upon how we found them, it did not appear that they had just been mortally wounded and moved to a location on their own and died. Where they arrived at, where we found them is not due to their own movement and they in fact had been left there," he said, adding that no note was found with the bodies.
The bodies of the two soldiers were spotted by coalition forces late Monday, but a military spokesman said their retrieval was delayed by the need to dismantle explosives planted in the area – suggesting the bodies may have been booby-trapped.
"They did not make immediate movement to go into that location because it was dark," said Caldwell, adding that due to the abundance of explosives already encountered "they wanted to proceed with caution... so they waited until daylight when they could bring in the explosive ordnance detachment and some other assets."
In Oregon, Tucker's family grieved in private. They said in a statement they were devastated by the news but heartened by the community support.
"Tom has gained a much larger family through this ordeal than he had when he left home to go help to free the Iraqi people and protect his country from the threat of terrorism," the family said.
"I think that everybody that knew Tom, and knows him, will be pretty devastated about it," Rick Strader, who worked with Tucker when Tucker was in high school, told CBS News correspondent Stephan Kaufman in Tucker's hometown of Madras. "It's horrible. They're over there doing a job and something like this happens and it really hits home. It hits this town really hard."
Menchaca's relatives are outraged at hearing grisly reports of his slaying through the media.
Menchaca's mother, Maria Vasquez, had already heard the reports when a member of the Army's casualty assistance office arrived at her Brownsville home Tuesday morning. She was sobbing when she answered the door of her home, accompanied by her niece, Felipa Gomez.
"She's hanging in there," and still holding on to hope that Menchaca will make it back alive, Gomez said. "She might be frightened, but she won't show it."
Vasquez later issued a statement written in Spanish that said, "I am against the war and I feel very hurt by what has happened to my son."
Ken MacKenzie, an uncle of Manchaca, lashed out at the U.S. government Tuesday morning, saying it did not do enough to find the men and keep them safe.
"I think the U.S. government was too slow to react to this. They should have had a plan in place," said MacKenzie, on NBC's "Today" show. "Because the U.S. government did not have a plan in place, my nephew has paid for it with his life."