The federal corruption trial of U.S. Representative Chaka Fattah of Pennsylvania is to begin on Monday with opening statements, three weeks after he lost the Democratic primary election for his seat in the Philadelphia area.

Fattah, 59, is accused of misusing hundreds of thousands of dollars in campaign, charity and federal grant money while engaging in a series of fraudulent schemes over several years.

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In 2007, prosecutors say, Fattah accepted a secret $1 million loan from a wealthy benefactor for a mayoral campaign that would prove unsuccessful, then misappropriated charitable and taxpayer funds to pay it back.

He is also accused of accepting bribes in exchange for official acts and using campaign funds to repay his son’s student loan debt.

The son, Chaka Fattah Jr., was himself convicted of federal charges in November stemming from an unrelated bank fraud and later sentenced to five years in prison.

The elder Fattah, who has served in Congress since 1995, faced his first primary challenge in 20 years and lost his re-election bid in April.

The congressman has repeatedly maintained his innocence since his indictment was announced in July 2015.

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Fattah faces a total of 23 charges, including racketeering, fraud, bribery, money laundering and conspiracy. Four associates of Fattah are also facing trial, which will take place in federal court in Philadelphia.