A Newport Beach doctor specializing in infectious diseases arrested late last year after he was accused of abusing nine patients may have abused dozens more men who were in his care, according to a lawsuit filed last week in Orange County.

Dr. William Thompson IV — a 56-year-old doctor who lived in Huntington Beach and had access to patients at Hoag Memorial Hospital Presbyterian for the last decade while also operating a private practice in Newport Beach — was charged in September 2023 with more than a dozen felony counts, including sexual penetration and sexual battery by fraud and forcible oral copulation.

Now, at least 73 patients are accusing Thompson of abusing them, too.

In a 730-page lawsuit filed Jan. 17, the alleged victims said that beginning in 2011 and continuing through 2023, Thompson used his authority as a doctor along with manipulative behavior to repeatedly subject them to unwanted sexual acts.

The alleged victims said Thompson’s actions occurred at Hoag Hospital, at his private medical offices and at his home, where he would instruct patients to visit him for invasive tests that they later found were unnecessary, according to the complaint.

The tests he performed on his patients “served no legitimate medical purpose, and were committed for no other reason than to satisfy Thompson’s own prurient sexual desires,” attorneys for the alleged victims wrote in the complaint.

“Thompson took advantage of his patients’ ignorance of the proper administration of genital, anal, and rectal examinations, so that (he) could force Plaintiffs to be fondled, stroked, and penetrated for (his) prurient sexual interests and sexual gratification.”

Thompson could not immediately be reached for comment Thursday. An attorney representing Thompson in his criminal trial did not return a request seeking comment.

Morgan Stewart, a partner at Manly, Stewart & Finaldi in Irvine, which is representing the 73 claimants, said Thursday that numerous “red flags” in Thompson’s behavior were ignored during the time that he worked as a specialist treating mainly gay men diagnosed with HIV/AIDS. But he said Thompson’s alleged abuses only stopped after he was arrested in September.

Thompson has since posted bond and is awaiting further proceedings in the criminal case brought against him.

All the claimants in the lawsuit were listed as John Does, but several men identified themselves by name Thursday. In a statement, one alleged victim, Johnny Chung, said he started seeing Thompson on the recommendation of his husband.

“Initially, (Thompson) was incredibly professional and courteous,” Chung wrote in a letter. “But after three months, he began to act inappropriately with each visit.”

Chung described how Thompson would insist that Chung undergo prostate and other examinations of his body parts “to be thorough,” Chung wrote.

“I left each exam feeling more violated and taken advantage of,” Chung wrote.

Chung’s husband, Michael Glockner, also said Thursday he was abused by Thompson. Glockner said he began seeing Thompson around 2016, when an illness confined him to a wheelchair.

Glockner said he was recommended to Thompson because he was the only doctor in South Orange County who specialized in the care he needed. During his time being treated by Thompson, Glockner said, the doctor increasingly began to push the boundaries of their patient-caretaker relationship.

He said Thompson subjected him to “aggressive prostate exams,” in which the doctor “would always want me to look at his private area to see how aroused he was,” Glockner said.

Several victims who spoke Thursday — who ranged in age from 25 to 68 years old — said they struggled to come forward with claims they were sexually abused because men are not typically seen as victims of sexual abuse.

In Glockner’s case, he said he’s taller than Thompson, and believed his strength and size meant that he could diffuse or put a stop to Thompson’s behavior toward him. But he said the abuse continued regardless.

When Chung told Glockner that Thompson had also abused him during an appointment, Glockner said he felt he needed to come forward to tell his story.

“I thought I was the only one he was doing this to,” Glockner, 68, said. “But when he did this to Johnny, that’s when I knew there were more of us.”

In a statement Thursday, officials at Hoag said they recognize “the courage it takes for former patients to come forward.”

The officials said Thompson was an independent medical practitioner who was not employed by the hospital group. But they said Thompson “had clinical privileges at Hoag Hospital” that were suspended following the filing of charges against him last year.