(CNN) - One was the mastermind, organizing the scheme's many parts and funneling millions of dollars.
One was the brains, acing standardized tests on behalf of wealthy parents' children.
And one was the coach, selling a spot at an Ivy League university for a hefty price.
These three figures -- William Rick Singer, Mark Riddell and Rudolph Meredith, respectively -- are at the center of the nationwide scandal in which 33 parents are accused of using their wealth and means to help their children game the college admissions system.
But those three names do not appear anywhere in the complaint, though the document gives enough clues to make clear who is who. Instead, they are named as Cooperating Witness 1, 2 and 3, and each agreed to plead guilty and to cooperate with the government in the hope of obtaining leniency when they are sentenced, the complaint says.
The information they provided was corroborated by court-authorized wiretaps, emails, documents, consensual recordings and interviews of other witnesses, the complaint says.
Here are their stories.
Singer, 58, was the central figure in coordinating the scheme. He was the owner of the college counseling and prep business known as "The Key" and the CEO of the Key Worldwide Foundation, the charity connected to it.
Through those organizations, Singer carried out his scheme to get the children of wealthy parents into top universities. His plan had two major parts: Facilitate cheating on standardized tests such as the SAT and ACT, and bribe college coaches and administrators to falsely designate the children as recruited athletes, even if they didn't play that sport.
In a June 2018 conversation with one parent, he referred to his plan as a "side door" into college.
"There is a front door which means you get in on your own. The back door is through institutional advancement, which is 10 times as much money. And I've created this side door in," Singer said.
To conceal the payments, he or an employee directed the parents to give money to the Key Worldwide Foundation as a charitable donation. Some of that money was then used to pay test administrators or coaches as part of the scheme, prosecutors said.
"(When) families pay for either, either takin' the test or goin' through the side door, all the money goes through my foundation, and then I pay it out to whoever needs to get paid," Singer told a parent in a recorded phone call in October 2018.
In all, Singer was paid about $25 million by parents as part of the scheme, said Andrew Lelling, the US attorney for Massachusetts.
The Key's website highlights Singer's expertise in education, and he is billed as the "CEO and Master Coach of the world's largest private Life Coaching and College Counseling Company." He even wrote a book about getting into college called, appropriately, "Getting In."
The website also said he created the first online high school, the University of Miami Online High School, and that he was previously CEO of one of India's largest call center companies.
Much of the success of the first part of Singer's plan -- getting higher scores for students on the SATs and ACTs -- relied on the smarts of 36-year-old Mark Riddell.
Riddell, a resident of Palmetto, Florida, was the director of college entrance exam preparation at IMG Academy, a private college prep school and sports academy in nearby Bradenton. He graduated from IMG Academy in 2000 and then attended Harvard University, where he played varsity men's tennis until graduating in 2004.
As part of the scheme, Riddell typically would take the standardized tests on behalf of the students or fix their incorrect answers, prosecutors said. Singer and Riddell also bribed the test administrators so that Riddell could take the test without being caught.
Riddell typically was paid $10,000 per test, according to court documents.
Interestingly, there is no allegation that Riddell stole the test answers or cheated to get the answers. He was just good at taking them.
So good, in fact, that Singer would have Riddell fly from his home in Florida to testing centers in Houston and Los Angeles, where the bribed test administrators worked.
In one case, Riddell was able to successfully fake a student's handwriting. In July 2018, a wealthy parent provided Singer with an example of her child's handwriting so that Riddell could imitate it when taking the test in his place.
Riddell also had a sharp eye for achieving a specific score. That same parent told Singer she wanted Riddell to get a 34 on the ACT on behalf of her son. (The maximum is a 36.) Riddell took the test for the student and then called Singer and predicted he would get a 35, the documents state. Later, the ACT score came back: He got a 35.
IMG Academy said in a statement on Tuesday that Riddell has been suspended indefinitely as it investigates the case.
"I want to communicate to everyone that I am profoundly sorry for the damage I have done and grief I have caused those as a result of my needless actions." Riddell said in a statement provided Wednesday by his attorney. "I understand how my actions contributed to a loss of trust in the college admissions process. I assume full responsibility for what I have done."
Rudolph "Rudy" Meredith had been the women's soccer coach at Yale since 1995 and was, as Yale boasted on its website, the winningest coach in Yale history.
The 51-year-old was named the Northeast Region Coach of the Year three times, and in 2005, he led Yale to its first outright Ivy League title in school history. He also previously served as an assistant coach for the US Under-23 women's national team.
Despite that sterling reputation, Meredith began conspiring with Singer in April 2015, according to court documents.
In November 2017, a Yale applicant's parents agreed to pay $1.2 million to get their daughter into Yale. Singer then sent Meredith the resume and personal statement of the student.
Separately, Singer sent an email to an employee to create a fake athletic profile for the student, the indictment says. In another email, Singer told the employee to write that the applicant had been on the "JR National Development Team in China," and adding "we are saying she got hurt this past spring, so was not recruited till now as she got her release late summer."
Singer then sent Meredith that athletic "profile" that falsely said the student was the co-captain of a prominent club soccer team in California, the documents state.
Meredith told the admissions office that the student was actually a soccer recruit and facilitated her admission to Yale, even though he knew she did not play soccer.
After the applicant was admitted, Singer mailed Meredith a check for $400,000, money drawn from the KWF charitable account.
In a second incident, Meredith tried to cut Singer out of the deal and work directly with a wealthy parent.
On or about April 12, 2018, he met with the father of a Yale applicant in a Boston hotel room and solicited a bribe from him. In exchange for $450,000, Meredith said, he would designate the applicant as a women's soccer recruit at Yale, the documents state.
Meredith accepted $2,000 cash as a partial payment at the meeting. He also told the father his bank account information, and another $4,000 was wired to him days later.
Meredith didn't know it, but the meeting was a set-up. FBI agents were secretly recording it, and the $4,000 was sent from a bank account under the FBI's control.
Despite that incident, Meredith remained Yale's coach until November 2018.
Yale President Peter Salovey said in a statement to the Yale community that he was "profoundly dismayed and disturbed" by the allegations against the coach.
"We do not believe that any member of the Yale administration or staff other than the charged coach knew about the conspiracy. The university has cooperated fully in the investigation and will continue to cooperate as the case moves forward," he said.
When they flipped
In general, defendants choose to cooperate with the government because they could receive a significant reduction in their prison time, said Neama Rahmani, an attorney at West Coast Trial Lawyers and a former prosecutor.
"Usually, the first people to cooperate get the advantage of leniency," he explained.
Meredith began cooperating with the FBI in April 2018, about the same time as the sting meeting with the FBI.
According to the indictment, he spoke on the phone with Singer just weeks later in a conversation in which Singer tried to persuade him to get other coaches in on the conspiracy.
"You can say he's doing it at, for this year I did (seven elite schools), we've done it everywhere," Singer said.
"Okay, see that might, yeah it definitely would make them feel more comfortable with all those places," Meredith responded.
Singer also bragged that he had done "760 of these this year, 96 the year before," the indictment states.
Meredith is set to appear in federal court in Boston on March 28.
Singer began cooperating with the government in or about late September 2018, the complaint says. But in October, he told several subjects about the investigation, and he was then charged with obstruction of justice.
Singer pleaded guilty Tuesday to racketeering, money laundering conspiracy, conspiracy to defraud the United States and obstruction of justice in federal court in Boston. His charity account, which contains $5.2 million, has been seized, prosecutors said in court.
Riddell began cooperating with the government in or about February 2019 and has agreed to plead guilty to mail fraud and honest services mail fraud, as well as conspiracy to commit money laundering, the complaint says. He is expected in federal court in Boston on April 12.