A former Merrill Lynch and Citigroup broker convicted of selling access to his brokerages' internal "squawk boxes" asked a judge to throw out his conviction and others, claiming that prosecutors hid evidence of their innocence.

Kenneth Mahaffy Jr. and five co-defendants found guilty last year asked U.S. District Judge John Gleeson to cancel their convictions, throw out the indictment or grant them a new trial. Gleeson heard oral arguments Thursday in Brooklyn, N.Y.

Lawyers for the men claim federal prosecutors withheld 27 transcripts of testimony from witnesses in a related civil lawsuit brought by the Securities and Exchange Commission. Mahaffy's lawyer said he discovered the documents in December, four days after the ex-broker was sentenced to two years in prison.

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