In court papers filed Monday in a New Jersey court, the lawyers said they learned of the slur in October, three years after Williams was tried for the shooting death of a limousine driver at his Hunterdon County home, The New York Post reported.

In 2004, a jury acquitted Williams of the most serious charges, deadlocked on a reckless manslaughter charge and convicted him of some lesser charges. Defense lawyers said that the slur could have been used as evidence to discredit the case against Williams at the trial.

Judge Edward Coleman could dismiss the manslaughter charge.

Williams' wife, Tanya, told The Post that her husband was denied his right to a fair trial.

"It is absolutely mind-boggling to learn that for five years, the Hunterdon County Prosecutor's Office has participated in a strategic cover-up to protect a racist," she said.