Three Marin County residents have been charged in a vast federal investigation into college admissions cheating and bribery, authorities announced Tuesday.

The 50 defendants in the nationwide case include William McGlashan Jr., of Mill Valley, and Todd and Diane Blake, of Ross, according to the criminal complaint. They are charged with conspiracy to commit mail and wire fraud for allegedly fixing spots for their children at the University of Southern California.

The charges carry a maximum sentence of 20 years, plus substantial fines, prosecutors said. Federal judges have broad sentencing discretion and terms are often much less than the maximum.

Federal authorities described the $25 million bribery case as the biggest college admissions scam ever prosecuted by the U.S. Justice Department. The investigation involved confidential witnesses, wiretaps, tracked phones and sloppily self-incriminating emails, authorities said.

The defendants include business executives, investors, a dentistry professor and the screen stars Felicity Huffman and Lori Loughlin.

“These parents are a catalog of wealth and privilege,” U.S. Attorney Andrew Lelling said in announcing the case, code-named Operation Varsity Blues.

Authorities allege the suspects bribed college coaches and other insiders to get their children into some of the most elite schools in the country. In some cases, college entrance exam administrators were allegedly paid to alter scores or get students extra time on tests.

The bribes were allegedly paid through Edge College & Career Network, a Newport Beach company, and an affiliated nonprofit, the Key Worldwide Foundation. The nonprofit, authorities said, offered an opportunity for tax-deductible payments into the scheme.

The founder, William Singer, agreed to plead guilty Tuesday to charges including racketeering conspiracy, prosecutors said.

No students were charged. Authorities said that the teenagers were often unaware of the fraud.

McGlashan, who has degrees from Stanford and Yale, is the managing partner of TPG Growth, part of the $103 billion investment fund TPG. He is also a board member of a TPG offshoot called the Rise Fund, which markets itself as socially and environmentally conscious. Other board members include Richard Branson and the singer known as Bono.

McGlashan allegedly agreed to pay $50,000 to the Key Worldwide Foundation for its help in getting a son into USC. According to the federal complaint, McGlashan used the service to get his son’s ACT exam scheduled at a “controlled” site in Southern California rather than at Marin Academy.

A “proctor” was flown in from Tampa to administer the test and correct the bad answers later, giving the teen a score of 34 out of a possible 36, authorities allege.

McGlashan and an admissions fraudster also discussed creating a fake sports profile for the teen, allowing him to get into USC as a recruited athlete, authorities said. The consultant asked for a photo of the teen so it could be digitally grafted onto the face of a football kicker.

“Let me look through what I have,” McGlashan allegedly said in a recorded conversation. “Pretty funny. The way the world works these days is unbelievable.”

The court filings suggest that McGlashan’s son was oblivious to his father’s alleged scheming.

McGlashan, 55, could not be reached for comment Tuesday. He is a member of the prominent McGlashan family that included former Marin County supervisor Charles McGlashan, who died in 2011.

TPG, the investment firm, said, “As a result of the charges of personal misconduct against Bill McGlashan, we have placed Mr. McGlashan on indefinite administrative leave effective immediately.”

McGlashan sits on the board of trustees at Marin Academy, the private prep school in San Rafael. According to the school’s website, he has two children at the school, one set to graduate this year and another in 2021.

Investigators also filed similar charges against a McGlashan associate — vintner Agustin Huneeus Jr., 53, of San Francisco — whose daughter goes to Marin Academy.

Marin Academy released a statement though a spokesman, Hervé Ernest:

“Earlier today, Marin Academy learned that numerous individuals were charged in a college admissions cheating scam. Among those named were two MA parents. We were shocked by these charges, and are especially concerned about the impact this will have on their children.

“The only information we have is what has been reported in the media and what is detailed in the criminal complaint. There is no indication that anyone who works at MA was aware of or participated in the alleged illegal and highly unethical behavior detailed in the charges.

“Like most independent schools, MA works diligently to prepare all of our students for college, and assists parents and students throughout the college application process. Our students can take the SAT or ACT college admissions tests here at MA, and those tests are proctored and/or supervised by members of our faculty. In fact, the complaint indicates the parents who were charged made arrangements for their students to take the tests at a site other than MA.

“MA’s athletic staff was not aware that these parents were allegedly misrepresenting their students’ athletic activities nor did members of our athletic department do anything to support recruitment of these students for college athletic teams mentioned in the complaint.”

In the case of the Blakes, they allegedly paid $200,000 to Key Worldwide Foundation and $50,000 to the University of Southern California Women’s Athletics department to get their daughter into that school.

Until 2018, Todd Blake was a trustee for nine years at the K-8 Ross School District, according to his Twitter account, where he also posted his excitement over his daughter’s enrollment at USC. Authorities described him an an entrepreneur and investor.

Diane Blake was a retail specialist and co-founder of Winston Retail Solutions who worked in the 1990s as director of retail marketing at Levi Strauss, according to her LinkedIn page.

The Blakes could not be reached for comment.

Court documents allege that in early 2017, Diane Blake emailed Singer saying her daughter was interested in USC but the mother “assumed the school was ‘in the reach stretch category.’” The Key foundation allegedly falsified volleyball records for the girl, saying she had won several volleyball honors and played for a club team that had qualified for the junior nationals.

USC’s senior associate athletic director, Donna Heinel, allegedly used that to present the Blakes’ daughter as a volleyball recruit. The Blakes’ daughter is enrolled at USC but is not on the roster for the women’s volleyball team, according to the indictment. In a February call, Singer told Diane Blake government officials were looking into student athlete records at USC.

“Yikes. Right,” Diane Blake said in reply. She said her daughter did not know her admission was rigged.

Federal authorities said the crimes occurred from 2011 through last month. The defendants include John Vandemoer, the former head sailing coach at Stanford University, and former coaches at Yale University, Georgetown University, Wake Forest University, the University of California at Los Angeles and the University of Southern California.

Other Bay Area parents charged in the case include residents of San Francisco, Healdsburg, Palo Alto, Atherton, Menlo Park and Hillsborough.

The Bay Area News Group contributed to this report.