The Pentagon's second in command struggled to explain on Thursday why he turned over a document plagiarized from Wikipedia as part of a private congressional briefing.

"It's not just that it was plagiarized from Wikipedia — every single graph in the document was taken from Wikipedia," House Intelligence Committee chairman Devin Nunes, R-Calif., said during a rare public hearing with Defense Department and intelligence community officials.

Deputy Defense Secretary Bob Work, who delivered the offending document during a private meeting with Nunes and other House committee chairmen, said he didn't know the origin of the document. "I would say that I am surprised that this information came from a Wikipedia page," Work told Nunes.

Such a filing would irritate lawmakers under any circumstances, but the fact that it pertained to the Pentagon's effort to downsize an air base in the the Azores — a move that Nunes has fought strenuously for years — ensured that it was a cause of particular frustration.

"We are here in a rare open session for this committee because we have struggled to get a lot of answers and provide transparency to the public, which is really one of our most important constitutional duties that we have as a legislative branch of government," Nunes said.