An uncorroborated video, investigators say, seems to show a child associated with an anti-government group beheading a prisoner.

CNN: U.N.: Both Syrian rebels and government forces guilty

The Justice Department called the threats to the California bridges "uncorroborated, " and some officials criticized the California governor for causing undue alarm.

CNN: Investigation: Concerns about alerting public

Taylor's lawyers have filed more than 40 grounds of appeal, arguing that the trial chamber's findings were based on "uncorroborated hearsay evidence".

BBC: Liberia's Charles Taylor appeals at The Hague

The disgruntled leaker claimed that the intelligence for this came from only one uncorroborated source one which the Joint Intelligence Committee had been reluctant to validate.

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Uncorroborated intelligence is the hardest type of intelligence to act on.

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In fact, Mr. Starr has stated in his referral to Congress that his own star witness is not credible except when her uncorroborated testimony conflicts with the president's, and then it proves his perjury.

CNN: Transcript: Opening statement of Rep. Nadler

It would have been far better to have trusted the public with the CIA analysts' full assessments than for the individual, sometimes uncorroborated pieces of raw intelligence to be released to the public without any analysis or context.

CNN: Presidents should share secrets with Congress

We have received sanctimonious lectures from the other side of the aisle about the rule of law, but the law does not permit perjury to be proved by the uncorroborated testimony of one witness nor does the law recognizes corroboration, the fact that the witness made the same statement to several different people.

CNN: Transcript: Opening statement of Rep. Nadler