SAN FRANCISCO (CBS SF) — Court documents unsealed Wednesday named a San Francisco contractor and permit expediter as the latest defendant involved in Mohammed Nuru Public Works scandal to plead guilty to charges, according to law enforcement.

United States Attorney David L. Anderson and authorities with the FBI and IRS on Wednesday announced that 70-year-old San Francisco resident Walter Wing Lok Wong had conspired for over 15 years to defraud the public in the corruption scandal involving Nuru, the former head of the San Francisco Department of Public Works.

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According to the unsealed charges, Wong allegedly conspired with Nuru and other unnamed San Francisco officials in schemes dating back as early as 2004 involving bribery, kickbacks and the concealment of material information. A second count alleged that Wong also conspired with Nuru and others to engage in money laundering in order to disguise and conceal the proceeds of their fraud.

Documents filed in court indicates that Wong intends to change his plea to guilty on both counts as early as July 6. According to the terms of a agreement filed in the documents, as part of his guilty plea, Wong will provide information, documents and testimony in the ongoing federal investigation into corruption in San Francisco city government, possibly in exchange for a reduced sentence.

The exact behavior underlying the crimes to which Wong was charged were submitted to the court in separate documentation to the plea agreement that was filed under seal and not available to the public, but government officials confirmed that Wong is the person previously described as “Contractor 2” in the 75-page complaint affidavit filed earlier this year against Nuru.

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Charges were previously filed against Nuru and local restaurateur Nick Bovis on January 28. Earlier this month, additional charges were filed against Sandra Zuniga — the Mayor’s Fix-It Director — and contractors Balmore Hernandez and Florence Kong. Zuniga has since been fired from her job.

Wong is the sixth defendant to be charged as part of the graft probe and the second to plead guilty. On May 13, Authorities announced that Bovis would plead guilty and cooperate with the government in the investigation.

“The charged conspiracy that we announce today is breathtaking in its duration and scope, alleging more than a decade of fraud and money laundering involving one of San Francisco’s highest ranking public employees, one of its most well-known permit expediters, and other city officials,” Anderson said in a press release announcing the charges and guilty plea. “As this investigation continues, the breadth and depth of the identified misconduct is widening. To everyone with a piece of public corruption in San Francisco, please understand that here in federal court we will distinguish sharply between those who cooperate and those who do not. If you love San Francisco, and regret your misconduct, you still have an opportunity to do the right thing. Run, don’t walk, to the FBI, before it is too late for you to cooperate.”

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Wong faces a maximum statutory penalty of up to 20 years in prison on each count, in addition to fines that could go as high as $500,000 or twice the amount of funds involved in the money laundering conspiracy.  The court may order additional terms of supervised release and restitution.