(CNN) Sen. Patty Murray, the top Democrat fighting Betsy DeVos' nomination to become education secretary, said Tuesday she is reviewing written answers the Michigan billionaire provided to the Senate that may include plagiarized material.

DeVos was approved by a Senate committee vote -- twice -- despite Democratic efforts to derail her confirmation process. The vote came after The Washington Post reported that DeVos had appeared to plagiarize answers she submitted to the panel.

Murray, whose questions spurred the plagiarism allegations, said at the Senate hearing that it appears the Michigan Republican's responses were "copied and pasted from previous statements, or are simple reiterations of the law and not true responses at all."

"Additionally, we just received responses to hundreds of written questions yesterday — less than 24 hours before a scheduled vote — and with no time for full review and to ask any follow-up questions," Murray said. "Though, I will say—upon initial review, many of the responses look copied and pasted from previous statements, or are simple reiterations of the law and not true responses at all."

Trump education adviser Rob Goad described the plagiarism allegations as "character assassination."

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