ST. LOUIS — In less than a week, Steve Stenger went from being the top elected official in Missouri's largest county to a convicted felon.

Stenger pleaded guilty Friday to federal corruption charges for providing political favors in exchange for campaign donations. Sentencing for the former St. Louis County executive is scheduled for Aug. 9. Each crime carries a possible sentence of up to 20 years in prison, though federal sentencing guidelines suggest a likely three to four years behind bars.

The indictment of the Democrat was announced Monday. He resigned about an hour later and surrendered his law license — Stenger is both an attorney and accountant. By Thursday, Stenger had agreed to plead guilty to all three counts in the indictment — bribery, mail fraud and theft of honest services.

Stenger politely answered U.S. District Judge Catherine Perry's questions during the court hearing but made no statement, and declined comment afterward. His attorney, Scott Rosenblum, told reporters that Stenger had a lot to be proud of during his career, "and today obviously is not one of those proud moments. But he has completely accepted responsibility for his mistakes in judgment, lapses in judgment and his conduct while in office as county executive."

Executive Assistant U.S. Attorney Reginald Harris said the indictment and Stenger's resignation and guilty plea "should send a message that the Department of Justice and federal law enforcement will not tolerate public corruption at any level of government."

Though he had a fast fall, Stenger had been under scrutiny for months.

The St. Louis Post-Dispatch reported about questionable contracts with campaign donors. The St. Louis County Council launched an ethics investigation. The FBI, U.S. Postal Inspection Service and the IRS criminal investigation unit had been looking into Stenger's activities since early 2018.

Assistant U.S. Attorney Hal Goldsmith said this week that investigators monitored or recorded several meetings and phone calls and obtained call records, including emails and texts.

Stenger was accused of ensuring that donor John Rallo and his companies — Cardinal Insurance and Cardinal Creative Consulting — obtained contracts with the county and received other favors.

He also was accused of ensuring that an unnamed company obtained a state lobbying contract from the St. Louis Economic Development Partnership. In January, the partnership's board of directors forced out Sheila Sweeney, a Stenger appointee.

In a statement, Interim County Executive Sam Page, a Democrat and frequent Stenger critic, said: Stenger "betrayed the trust that St. Louis County residents placed in our government. I am committed to reforming County government so that pay-to-play politics never infects it again."

Federal prosecutors have said the investigation continues and have declined to say if Rallo or anyone else may face charges.

Stenger defeated incumbent Democrat Charlie Dooley in the 2014 primary and won that year's general election. Even under the cloud of investigations, Stenger fought off a strong challenge from businessman Mark Mantovani in the 2018 Democratic primary and easily defeated his Republican challenger in November.

About 1 million people live in St. Louis County.