The U.S. Marine who mysteriously vanished in Iraq and reappeared in Lebanon nearly three weeks later has been cooperating with specialists questioning him at a U.S. military hospital, a key figure in the debriefing told The Associated Press on Monday.

Cpl. Wassef Ali Hassoun (search) was being debriefed at Landstuhl Regional Medical Center (search) by intelligence specialists, psychologists, physicians and a Muslim chaplain, said Army Lt. Col. Sally Harvey, a clinical neuropsychologist who is overseeing the questioning.

"He has fully engaged in the process," Harvey said in a telephone interview from Landstuhl. "His spirits are good and he's participated fully."

Harvey was not permitted to say what Hassoun might have told investigators about his disappearance June 20 from his base near the troubled Iraqi city of Fallujah (search).

In the three weeks that the 24-year-old was missing, various conflicting reports emerged about him — including that he was beheaded by militants who abducted him. On June 27, Arab television showed a videotape of him with his eyes covered by a white blindfold and a sword held above his head.

He then showed up July 8 at the U.S. Embassy in Beirut, but it was unclear how he reached Lebanon and contacted American officials. The Navy has said it is investigating whether the entire kidnapping might have been a hoax.

But Harvey said the questioning at Landstuhl is no different than what has been undergone by others who have escaped captivity in Iraq.

"It's exactly the same process that Jessica Lynch went through. ... It's exactly the same process Tommy Hamill went through — there is nothing different, nothing unique, about how we are treating Cpl. Hassoun," she said.

Lynch, an Army supply clerk, was captured March 23, 2003, in Iraq and was later found by U.S. commandos in a hospital in the southern Iraqi city of Nasiriyah. Hamill, a civilian truck driver, was taken hostage in Iraq on April 9 and managed to escape his captors on his own. Both were treated at Landstuhl before returning to the United States.

The debriefing team was conducting "survival, evasion, resistance, and escape" questioning of Hassoun, and the results would be passed back to try and help others in Iraq, said Marine Corps Europe spokesman Maj. Tim Keefe.

"Some of those lessons can go immediately back to people that are there and in that way they may have something that can save someone else's life," Keefe said.

Hassoun is expected to be able to return to his home unit in Camp Lejeune, N.C., "in a couple days," Keefe said.

On his arrival at Landstuhl on Friday, doctors said that Hassoun seemed to be in good health but had lost 20 pounds and was having trouble sleeping.

He is sleeping better, and has been talking on the telephone with his mother in Lebanon and his brother in Utah as well as other family members, said hospital spokeswoman Marie Shaw.

"He is in good spirits, he's doing well," she said. "Today he's going to get a haircut and shave and look like a Marine again."

She said that the debriefing team had been speaking with Hassoun regularly.

"Most of it's just conversations, and it's done in an atmosphere as comfortable as possible for him," she said.