NEW YORK -- In the wake of NBC Nightly News anchor Brian Williams' suspension for lying about being on a helicopter that took fire in Iraq in 2003, questions are emerging over another of his Iraq exploits. Among other things, these questions involve war memorabilia the anchor claims to have received as gifts, including a Navy SEAL's knife and a piece of the helicopter from the raid that killed Osama bin Laden.

Starting in 2011, Williams began talking about a 2003 experience with SEAL Team 6, the elite team that killed bin Laden inside Pakistan on May 1, 2011. But at least one SEAL and comments from the U.S. Special Operations Command cast doubt on that tale.

"We have some idea which of our special operations teams carried this out," Williams said on "The Late Show With David Letterman" the day after the raid. "It happens to be a team I flew into Baghdad with, on the condition that I would never speak of what I saw on the aircraft, what aircraft we were on, what we were carrying, or who we were after."

"Now, people might be hearing about SEAL Team 6," Williams said the next night, May 3, 2011, on Nightly News." "I happen to have the great honor of flying into Baghdad with them at the start of the war."

While it's clear that Williams flew into Baghdad on April 9, 2003, and reported from the airport using a flashlight to illuminate his face, he didnt get into specifics that evening, or on other network broadcasts. A Lexis-Nexis search of network transcripts didn't yield other examples of Williams mentioning the ride with SEAL Team 6.

But a year after the bin Laden raid, in May 2012, Williams elaborated in another appearance on Letterman's show.

I flew into Baghdad, invasion plus three days, on a blackout mission at night with elements of SEAL Team 6, and I was told not to make any eye contact with them or initiate any conversation, Williams said. (Three days after the U.S. invasion would have been March 22, 2003, not April 9, 2003, which was the day Williams broadcasted from the Baghdad airport.)

It's possible Williams did fly into Baghdad with SEAL Team 6 and didn't mention it for over eight years because he had agreed not to discuss the unit's activities, speaking out only after the SEAL Team received attention for the bin Laden raid. But NBC has not confirmed Williams' account of the events. Justin Balding, who was a producer with Williams at the start of the Iraq war and still works at NBC, did not respond to The Huffington Post's request for comment on the flight into Baghdad. An NBC News spokeswoman declined to comment on the flight with SEAL Team 6.

In the 2012 "Late Show" appearance, Williams also recalled carrying a box of Wheat Thins, which he said a hungry special operator dug into with a hand the size of a canned ham." They got to talking, and Williams told the commando how much he admired his knife. "Darned if that knife didnt show up at my office a couple weeks later," Williams told Letterman.

The gifts didn't stop there: More than eight years later, Williams had apparently maintained his relationship with one or more members of the fearsome SEAL Team 6. According to Williams' recollection, one special operator appreciated his relationship with the anchor so much that he sent Williams a precious token from the bin Laden raid.

"About six weeks after the Bin Laden raid, I got a white envelope and in it was a thank-you note, unsigned," Williams said on "Letterman" in January 2013. "And in it was a piece of the fuselage of the blown-up Black Hawk in that courtyard. Sent to me by one of my friends."

The SEAL Team arrived inside bin Laden's Abbottabad complex by means of a specially modified, highly advanced stealth Black Hawk helicopter. The helicopter was reportedly covered in special coating to prevent radar detection.

In February 2014, Williams elaborated on the helicopter gift in another media appearance, this time on the sports talk show hosted by Dan Patrick . "Its one of the toughest things to get," he said, "and the president has a piece of it as well ... Its made of a material most people haven't seen or held in their hands."

The White House declined to comment on whether President Barack Obama owns a piece of the stealth Black Hawk.

If Williams' story is accurate, he truly does hold a piece of history -- and a piece of highly sensitive U.S. military hardware. In fact, the helicopter was so valuable that its return to the United States became a minor diplomatic issue of its own in the wake of the bin Laden raid.

The NBC News spokeswoman declined to comment on whether Williams owns the mementos.

Williams was based in Kuwait early on in the Iraq invasion, which began on March 19, 2003. In a foreword to NBC's book Operation Iraqi Freedom, former Nightly News anchor Tom Brokaw wrote that Williams kept us apprised of missile attacks launched at Kuwait.

At the start of the war, NBC had four teams embedded with military units, led by correspondents Kerry Sanders, Chip Reid, Dana Lewis and David Bloom. (Bloom died just weeks into the war.) SEAL Team 6 is not one of the units listed in the book.

Williams was reporting from Kuwait on March 26, 2003, when he first mentioned the now-infamous Chinook helicopter incident. That night, Williams discussed a helicopter that was forced down after being struck by a rocket-propelled grenade, but contrary to later retellings, did not say he was on the aircraft. Operation Iraqi Freedom mentions the incident as well, but also doesnt claim that the anchor's aircraft was the one hit.

From his early position in Kuwait, Williams was able to observe special operations units "staging for missions into Iraq, according to the book. Theres no mention in the book of how Williams was later transported to Baghdad.

One former SEAL who spoke to HuffPost questioned Williams' account from start to finish.

"My initial reaction is it sounds completely preposterous. There's a healthy dislike towards embedded journalists within the SEAL community," said Brandon Webb , a writer and former SEAL sniper who helped train Chris Kyle. "I can't even remember an embed with a SEAL unit. And especially at SEAL Team Six? Those guys don't take journalists with them on missions."

"We do not embed journalists with this or any other unit that conducts counter-terrorism missions," United States Special Operations Command spokesman Ken McGraw told HuffPost about SEAL Team 6. It's not clear whether Williams could have come into contact with the team outside the formal embed process.

McGraw did not offer a debunking of Williams' tale. But he did raise one key point -- the helicopter was destroyed after the commandos left the compound, presumably on a timer. So any piece that went to Williams would have had to have been sent after the chopper was returned to the United States.

"We don't have any idea what someone could have sent Mr. Williams and what kind of claim that person may have made," said McGraw. "But, while the details of the raid remain classified, I can say the aircraft was not blown up until after US forces had left the compound."

When NBC News President Deborah Turness announced Tuesday night that Williams would be suspended for six months, she noted that the networks internal review was still ongoing. Richard Esposito will continue leading the network's inquiry into Williams coverage and his public recollections about his experiences in Iraq and during Hurricane Katrina . Further instances of false claims or exaggerations could determine not only whether Williams ever gets back in the "Nightly News" chair, which many at the network consider unlikely, but whether he has any future in journalism at all.

If Williams does own a piece of the fuselage, his repeated references to it in the media raise their own issues. Many details of the bin Laden raid are still highly classified. SEALs involved in the raid who have spoken about it publicly -- Matt Bissonette and Robert ONeill -- have faced legal troubles with the Pentagon and a Naval Criminal Investigative Services probe . Even former CIA Director Leon Panetta faced a Defense Department inspector general investigation for leaking details of the raid to the filmmakers behind "Zero Dark Thirty."

"Shame on him if he was given a piece of helicopter," said Webb. "By telling the world, he's basically caused a reason for the inspector general to investigate that command."

Now that the onus is on Williams to prove the veracity of his war stories, Webb said there is an easy way for the anchor to confirm this one.

"It seems very strange that professional operators are going to take a souvenir off a classified stealth helicopter and then send it to Brian Williams," he said. "And you know, if Brian wants to re-establish his credibility, let's have him show us a picture of the piece, let's see it."

This article was updated after publication with comments from the United States Special Operations Command.