When Federal Bureau of Investigation agents arrested dozens of wealthy parents, college coaches and others in March 2019 at the crescendo of the Operation Varsity Blues investigation, they released a 204-page affidavit detailing the payments and taped conversations that they say provide evidence of a brazen college admissions cheating scheme.

As part of a trial under way in Boston for two parents, John Wilson and Gamal Abdelaziz, federal prosecutors have entered as evidence audio from more than a dozen phone calls and meetings...

When Federal Bureau of Investigation agents arrested dozens of wealthy parents, college coaches and others in March 2019 at the crescendo of the Operation Varsity Blues investigation, they released a 204-page affidavit detailing the payments and taped conversations that they say provide evidence of a brazen college admissions cheating scheme.

As part of a trial under way in Boston for two parents, John Wilson and Gamal Abdelaziz, federal prosecutors have entered as evidence audio from more than a dozen phone calls and meetings between college counselor William “Rick” Singer and clients.

Mr. Wilson and Mr. Abdelaziz have pleaded not guilty to fraud and bribery-conspiracy charges; Mr. Wilson also denies charges of aiding and abetting in fraud and bribery and filing a false tax return. Their lawyers argue that they were duped by Mr. Singer and that they believed they were making legitimate donations.

Listen to the Calls

Scroll to hear call excerpts of conversations between Rick Singer and parents in the Varsity Blues college-admissions scandal.

They were recorded with the authority of a wiretap and, later, with Mr. Singer’s permission after he began cooperating with the government. To date, 47 people have pleaded guilty or agreed to do so. In addition to Messrs. Wilson and Abdelaziz, six more are scheduled for trial later this year and in early 2022.

Some of the taped conversations center on the two main illicit opportunities Mr. Singer offered, as he laid them out to prospective clients or reviewed his actions with those who already used his services. In the bribery scheme, he paid coaches or their programs to admit his clients’ children as recruited athletes, regardless of the teens’ ability. In the testing scheme, he directed families to have teens assessed for learning disabilities so they could receive extra time on college-entrance exams. He then sent them to testing sites where a corrupt proctor rigged their scores.

Now, rather than read the transcripts, you can hear the conversations—and, notably, how the parents identified in each segment below engage with Mr. Singer.

Gordon Caplan speaking to the news media outside federal court in Boston, in October 2019.

Photo: Steven Senne/Associated Press

Gordon Caplan

In summer 2018, Mr. Singer connected with lawyer Gordon Caplan via Scott Treibly, a former tennis coach who advised student athletes on college admissions, according to people familiar with the investigation. They discussed the prospect of using his testing scheme to help boost the chances of admission to a top school for Mr. Caplan’s daughter, Rachel, who he said was a very strong but not top-ranked tennis player.

The exchange started with a failed joke about Gordon Gekko from the movie “Wall Street,” then turned to business as Mr. Singer explained why Mr. Caplan’s daughter wasn’t doing anything too out of the ordinary by getting extended time on a college admissions test.

Mr. Caplan pleaded guilty to fraud conspiracy and was sentenced to one month in prison, one year of supervised release, community service and a fine.

John Wilson and his wife leaving federal court in Boston last month.

Photo: David L. Ryan/The Boston Globe via Getty Images

John Wilson

In a Sept. 15, 2018, conversation, Mr. Singer walked client John Wilson through the benefits of paying to have his twin daughters tagged as recruited athletes in the admission process.

Mr. Singer summarized the advantage athletes have over other applicants, above and beyond what children of donors or legacies can expect, while Mr. Wilson interjected with a few questions.

In an Oct. 27, 2018, phone call, Mr. Singer told Mr. Wilson that he had secured a spot for one daughter as a sailor via John Vandemoer, Stanford’s sailing coach. (Mr. Vandemoer has pleaded guilty for his role in the scheme and was fired by the university.) He relayed the good news to his client.

Mr. Wilson pleaded not guilty to charges including fraud, bribery and filing a false tax return, and is currently on trial.

Defense lawyers have claimed that Mr. Singer made the plan seem above board and purposely misled their clients. Addressing the tapes concerning his client, Mr. Wilson’s lawyer said, Mr. Singer didn’t use words like “bribe” or “fake profile.”

Bruce Isackson leaving federal court in Boston in April 2019.

Photo: Michael Dwyer/Associated Press

Bruce Isackson

In an Oct. 24, 2018, phone call, Mr. Singer spoke with client Bruce Isackson about their arrangement to land his daughters Audrey and Lauren at UCLA and USC, respectively, in recent years. As part of his cooperation with federal agents, Mr. Singer fed Mr. Isackson a phony story, saying he needed to go over the scheme because his foundation was being audited, and that there might be questions about Mr. Isackson’s payments. Former federal prosecutors say the IRS cover story often works because the threat of an audit gets people to panic and discuss how they will deal with the feds.

Mr. Isackson pleaded guilty to charges including fraud conspiracy and money-laundering conspiracy, and agreed to cooperate with federal authorities; he hasn’t been sentenced yet.

Gamal Abdelaziz

One common question about the scheme, and why it didn’t fall apart sooner, was why schools didn’t notice their recruited student athletes often didn’t join the teams to which they were admitted. Mr. Singer suggested families give a cover story of an injury if anyone grew suspicious about the student’s absence from a team.

There is no indication USC asked about Mr. Abdelaziz’s daughter after she began school there, but in January 2019, at the direction of law-enforcement agents, Mr. Singer told the father that such inquiries had come up about Sabrina.

Mr. Abdelaziz pleaded not guilty to fraud-conspiracy and bribery-conspiracy charges and is currently on trial. His lawyers have said that Mr. Singer lied about where the money was going and that their client didn’t know about the fake athletic profile submitted for his daughter.

Mr. Wilson’s lawyer says Mr. Wilson’s son was a legitimate water-polo player, that any embellishments to his résumé were Mr. Singer’s doing and that Mr. Wilson also thought he was making a standard gift.

A prosecutor said the evidence shows that the falsified profiles were “sent to and received in email accounts that the defendants actually used.”

Write to Melissa Korn at melissa.korn@wsj.com and Jennifer Levitz at jennifer.levitz@wsj.com

Corrections & Amplifications
Donna Heinel is an ex-athletics administrator at the University of Southern California. An earlier caption with this article incorrectly said her surname is Heinal. (Corrected on Oct. 6)