A memo backing Nebraska Senate candidate Shane Osborn's decision to land a surveillance plane in China following a 2001 midair collision came from a friend in the Navy, not the U.S. Navy officially, a report in the Omaha World-Herald revealed Monday.

Osborn (R) is a former Navy pilot who gained celebrity status after he guided the damaged aircraft to safe landing. But he's faced some criticism because the Chinese were reportedly able to recover some documents from the plane. The Chinese detained and interrogated Osborn and his crew for 12 days, his campaign said.

Osborn released a memo on Navy letterhead last month that supported his decision. Here's the World-Herald with more:

The memo, written Aug. 8, 2013, on Navy letterhead, is titled “Disposition of actions by EP-3E flight crew on April 1, 2001.” It explains that Osborn's plane was authorized to land on China's Hainan island “due to the extreme circumstances and condition of this aircraft.”

But The World-Herald has learned that the unsigned memo was not authorized by the Navy, or vetted through normal channels, and was written as a favor to Osborn by a Navy buddy working at the Pentagon.

The Navy told the paper it could not authenticate the memo. The World-Herald later learned that it the author of the memo was a Navy commander who wrote it because a friend of Osborn's asked him to do so. The Osborn friend, John Comerford, also survived the crash.

Osborn told the newspaper of the memo, "We haven't posted it on our website," adding, "It's not like we're putting it out in a mass email to supporters."

A former state treasurer, Osborn is running for the seat being vacated by retiring Sen. Mike Johanns (R) that has split the tea party. Freedomworks backs Osborn while the Club For Growth and Senate Conseravtives Fund are supporting Midland University President Ben Sasse.

The pasts of both Sasse and Osborn have come under heavy scrutiny in the campaign. Sasse has received attention for once advocating for Medicare Part D, which the Club For Growth opposes.