(CNN) Democrat Dan McCready is withdrawing his concession in a North Carolina congressional race where investigators are probing allegations of election fraud.

Dan McCready

McCready got 905 fewer votes than Republican Mark Harris in the 9th District race. But the state elections board has refused to certify the results as it investigates potential misconduct with absentee ballots, making it the last undecided House contest in the country. The board could ultimately order another election.

McCready had previously conceded the race to Harris, but withdrew that concession Thursday.

"I didn't serve overseas in the Marines to come home to NC and watch a criminal, bankrolled by my opponent, take away people's very right to vote," McCready tweeted. "Today I withdraw my concession and call on Mark Harris to end his silence and tell us exactly what he knew, and when."

BREAKING: Dan McCready tells me he is officially withdrawing his concession.



In an exclusive interview, he tells me he thinks Mark Harris knew what McCrae Dowless was doing and that Harris bankrolled "criminal activity." #ncpol #NC09 @wsoctv pic.twitter.com/m7LhB2vGnM — Joe Bruno (@JoeBrunoWSOC9) December 6, 2018

His reversal comes as the state elections board, as well as local and state prosecutors, investigate whether Leslie McCrae Dowless, a veteran operative in Bladen County who was hired by a consulting firm the Harris campaign paid $400,000, altered absentee ballots or collected them from voters but never turned them in.

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