LOS ANGELES (CBSLA) — Additional charges have been filed against former USC gynecologist George Tyndall, who allegedly sexually assaulted more than 20 young women while working at the university.

Five counts of sexual penetration of an unconscious person and one count of sexual battery by fraud were added to Tyndall’s case, L.A. District Attorney Jackie Lacey announced on Thursday.

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The new charges allege that Tyndall sexually assaulted five women while working at a USC health center between 2011 and 2015.  Tyndall, 72, was already charged in June 2019 with 18 counts of sexual penetration of an unconscious person and 11 counts of sexual battery by fraud — all of which are felonies.

In July 2019, Tyndall plead not guilty to the original charges against him. An arraignment is expected to be held on July 24 for the new charges.

USC began to investigate allegations of improper pelvic exams and making racist and sexually inappropriate remarks in 2016, but Tyndall and the university did not part ways until June 2017.

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More than 400 women have accused Tyndall of sexual misconduct. USC announced in October it had reached a $215 million settlement in principle on a class-action lawsuit brought against Tyndall. The alleged crimes detailed in the charges date back to 2009, but hundreds of former patients have sued Tyndall and USC, accusing the university of failing to respond to allegations of abuse, some as far back as the 1980s.

In February, the U.S. Department of Education announced the school would be under three years of federal monitoring, citing systemic failures in the University of Southern California’s response to allegations of sexual misconduct against Tyndall.

The investigation, opened in May 2018, found that the university was notified of allegations of misconduct by Tyndall and failed to appropriately respond to those accusations, potentially subjecting female students to continued sex discrimination.

All 21 victims, who range in age from 17 to 31, said they went to the campus facility for annual exams or other treatment, according to prosecutors.

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If convicted as charged, Tyndall now faces a possible maximum sentence of 64 years in state prison.