Mayor Ron Gonzales was indicted by a county grand jury Thursday on six counts, his office said, but the allegations were not immediately clear.

Prosecutors have said they were investigating whether Gonzales committed any crime by negotiating a trash hauling contract with Norcal Waste Systems that cost taxpayers an additional $11.25 million in labor costs.

Gonzales and aide Joe Guerra each posted $50,000 bond Thursday morning and were scheduled to appear Monday in Santa Clara County Superior Court, the mayor's office said. Gonzales' lawyer, Allen Ruby, said a copy of the booking slip was difficult to read, but he believed there were some conspiracy counts.

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Gonzales denied any wrongdoing and rejected calls to step down, said deputy chief of staff Deborah Herron.

"Mayor Gonzales has not seen the indictment," a statement from the mayor's office said. "He broke no laws."

Guerra's lawyer, Alan Lagod, also said he had not seen an indictment. Norcal was named in four counts of the indictment, but denied any wrongdoing, said Bill Goodman, an attorney for the firm.

The district attorney's office declined to comment, but scheduled a news conference Friday on the results of the Norcal grand jury investigation.

A lawyer hired by the city to investigate the garbage contract said in December that Gonzales and Guerra violated city policy requiring independence and impartiality when they privately assured Norcal the city would cover its increased labor costs.

Gonzales failed to disclose to city councilors that $1 of a $1.40 per month garbage rate increase was intended to cover labor costs. Gonzales had acknowledged that he agreed to the deal without informing the council, but said members knew it was happening.

The City Council censured Gonzales in December for the deal.

Prosecutor George Kennedy has said that civil grand jury findings and those of an independent investigator raised "serious questions" about the deal-making process.

Vice Mayor Cindy Chavez and three city councilors called on Gonzales to step down immediately.

"Being the mayor of the 10th largest city is a demanding job," Chavez said. "He needs to be able to focus his energy either on the business of the city or his own personal business."

Chavez, who is running to succeed the mayor, said she would not seek to be named acting mayor if Gonzales resigned. Gonzales is barred by city law from seeking a third term. Both are Democrats.

Gonzales became one of the first Hispanic mayors of a major U.S. city in 1998, and addressed the 2000 Democratic National Convention in Los Angeles.

Two months later, he admitted an extramarital affair with a 25-year-old subordinate. The city soon struggled under record deficits following the dot-com bust and the mayor suffered a stroke during his State of the City address in 2004. Since then, the city has been racked by contract scandals.

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