Mario Juarez, the government's central witness in the federal corruption trial of former Oakland Mayor Sheng Thao, began testifying Friday in Oakland, ABC7 News reports. Prosecutors had signaled he would take the stand next week, according to the station, but he appeared unexpectedly at the federal courthouse Thursday.

Who Juarez is

Juarez is an Oakland businessman and political operative who has pleaded guilty to conspiracy to commit bribery. He agreed to testify for the government in hopes of a lighter sentence, KQED reports. In 2022 he co-founded Evolutionary Homes with recycling executive David Duong and his son Andy Duong. The company planned to turn shipping containers into housing for people leaving homelessness.

Prosecutors allege the Duongs backed Thao's 2022 campaign and gave her partner, Andre Jones, a $300,000 no-show job at Evolutionary Homes. In exchange, they say, Thao agreed to help the company get a city contract, elevate certain city staffers at the Duongs' and Juarez's request, and help California Waste Solutions, the Duongs' other business, with city deals. Thao, Jones and both Duongs have pleaded not guilty.

What the jury has already heard

ABC7 reports that prosecutors have played secret recordings of Evolutionary Homes board meetings that they say show Juarez was the main contact with Thao and Jones. In one recording, Juarez describes a call in which Jones allegedly asked for $20,000 on top of $85,000 he had already received. On Thursday, former City Administrator Jestin Johnson testified that Thao told him to meet David Duong and tour the company's showroom, according to the station.

The fight over his credibility

KQED reports that defense lawyers have called Juarez a "consummate hustler" and pointed to 33 lawsuits he was involved in between 1992 and 2022. "Juarez is the beating heart of the government's case," Andy Duong's attorney Winston Chan told jurors in his opening. Prosecutor Abraham Fine has said Juarez is "no angel" but that his account matches thousands of texts and recordings.

According to KQED, Juarez's partnership with the Duongs collapsed in 2024. On May 3, 2024, he found himself locked out of the company's office, and an altercation with the Duongs turned violent. Later that day he reported to Oakland police that he had been assaulted and made corruption allegations and sat for his first FBI interview that June. For earlier testimony, see our story on the FBI agent's cross-examination.