The University of Southern California has received hundreds of complaints about a former school gynecologist suspected of conducting inappropriate exams for decades, prompting the resignation of the school president and a police investigation.

More than a dozen lawsuits have been filed and police are talking to more than 50 women who complained, so far.

Whether Dr. George Tyndall faces charges, though, depends on if complaints about creepy comments, improper photos in the exam room and uncomfortable probing went beyond dubious doctoring and into the criminal realm.

The university has come under fire since the Los Angeles Times reported earlier this month that complaints and comments about Tyndall’s care went unheeded by the school for decades and that USC failed to report him to the medical board even after the school quietly forced him into retirement last year.

Two administrators were fired and President C.L. Max Nikias agreed to step down after criticism for leadership failures during a string of scandals that included reports by the Times that the university’s former medical school dean used drugs with criminals and was present when a woman overdosed in a Pasadena hotel room.

Lawsuits accuse Tyndall, the school’s staff gynecologist for nearly three decades, of using his authority to sexually abuse women between 1990 and 2016. The suits allege the school concealed the conduct.

Tyndall was a “serial sexual predator” who groped breasts and used his fingers to penetrate rectums and vaginas for no medically necessary purpose, attorney John Manly said in a suit filed Friday. Tyndall is also accused of taking close-up photos of genitalia and commenting on the bodies of women, their race and sexual activity.

In some instances, Tyndall is accused of conducting vaginal exams without gloves when students were only seeking birth control.

Tyndall, 71, denied wrongdoing in interviews with the Times. He didn’t return phone calls or an email from The Associated Press. It wasn’t known Tuesday if he has an attorney.

USC concluded in 2016 that Tyndall violated policies on harassment and making racially discriminatory and sexually inappropriate remarks, but two criminal law experts it consulted said there was no criminal activity to report, the school said.

The allegations have similarities with the case of Larry Nassar, the disgraced former sports doctor at Michigan State University and USA Gymnastics now serving multiple life terms in prison. Michigan State agreed to a $500 million settlement with more than 300 of his victims.

One key difference with the high-profile case involving Olympic champions, though, is that Tyndall as a gynecologist could argue his treatments were within the scope of his medical expertise.

Internal investigations by USC got mixed reviews on Tyndall’s practice of using a finger before inserting a speculum during pelvic exams. One expert said it could be considered acceptable, though another review found it outdated.

Some women who have spoken about their encounters — some of whom were on their first visits to a gynecologist — said they didn’t realize their treatment was improper until they saw recent news stories.

“These women had no idea they were being sexually abused,” said attorney Ron Labriola, who is working with Manly. “They said it was odd, it was weird, but that’s different from (perceiving it) as a sexual assault.”

That could make it challenging but not impossible for authorities to pursue charges against Tyndall, particularly given the potential number of complaints.

A jury in Casper, Wyoming, recently convicted a gynecologist who touched women in ways they said were unusual and made them feel uncomfortable. Prosecutor Mike Blonigen said there is often no physical evidence or eyewitnesses in such cases and the difference between proper care and a crime can be subtle.

“Some of the challenges are distinguishing between clumsy execution in the procedure and illegal touching. That’s hard to do,” Blonigen said. “The thought that my doctor is molesting me is a hard thing to process.”

Dr. Paul Harnetty was sentenced to 20 to 30 years in prison on two counts of second-degree sexual assault.

Successful prosecutions almost always involve multiple women who can provide corroborating testimony, Blonigen said. In Harnetty’s case, six patients testified against him, though he was cleared of several counts.

If there’s a single victim, the case can devolve into a he said-she said dispute, said Michele Goodwin, a law professor at the University of California, Irvine. In the medical environment, a typical defense is that it was part of an exam and there were no supporting eyewitnesses or video.

In Tyndall’s case, female nurses or medical assistants known as chaperones who often accompany male gynecologists during exams, had complained about his behavior, including his use of a camera, the Times reported. Those colleagues could provide valuable testimony.

But Goodwin pointed out that chaperones can’t see everything in such an intimate setting. “A gynecological exam can include things that are very graphic,” Goodwin said. “That is also what makes these types of cases so frightening for these young women … The abuse happens to be hidden in the worst way.”

If investigators can’t find physical evidence of abuse, they will see if women reported incidents at the time to roommates, family members or others and whether medical records match up with when they said they were abused.

One advantage prosecutors have is they can present evidence of similar misconduct the defendant may not be charged with to show a pattern, said criminal defense attorney Robert A. Schwartz, who is not involved in the case.

Jurors were unable to convict Bill Cosby of sexual assault at his first trial when only one additional woman testified against him. Cosby was convicted at a second trial after five other women testified about prior bad acts dating to the 1980s.

“Most doctors as a defendant in a criminal case would get the benefit of the doubt,” Schwartz said. “What tips the scales against the doctor and his testimony would be the sheer volume of complaints.”

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