Two businessmen sought to use their wealth to fraudulently secure spots for their children at elite U.S. universities, a federal prosecutor said on Monday at the start of the first trial in the "Operation Varsity Blues" college admissions scandal.

Former casino executive Gamal Aziz and private equity firm founder John Wilson paid hundreds of thousands of dollars to secure spots for their children at the University of Southern California (USC) as "phony" athletic recruits, Assistant U.S. Attorney Leslie Wright told a federal jury in Boston.

She said they did so with the help of William "Rick" Singer, a California college admissions consultant who prosecutors have said masterminded a vast scheme to help wealthy clients get their children into top schools through fraud and bribery.

"It was a sprawling conspiracy that extended from coast to coast," Wright said in her opening statement. "None of these kids were getting recruited to play collegiate sports without the money."

Both men deny wrongdoing, saying they believed the money was for donations to the universities, not bribes.

"Giving money to a school with a hope that it gets your kid in is not a crime," Brian Kelly, Aziz's lawyer, told jurors.

He said Singer never told his client, a former Wynn Resorts Ltd executive, that his money would be used to bribe USC athletics officials. Aziz trusted Singer and "had no inkling singer was a skilled con man," Kelly said.

The two men were charged 2-1/2 years ago along with dozens of business executives and celebrities in a scandal that exposed the lengths wealthy parents would go to attain spots for their children at top schools as well as inequalities in higher education.

Fifty-seven people have been charged in the probe since 2019, including actresses Lori Loughlin and Felicity Huffman, who were among 46, including 32 wealthy parents, who have since pleaded guilty.

Aziz, also known as Gamal Abdelaziz, is the former president of Wynn's Macau subsidiary. Wilson is a former Gap Inc and Staples Inc executive who founded Hyannis Port Capital.

Prosecutors say Singer through his college counseling business, The Key, offered not just legitimate services to parents worried about their children's college prospects but also the use of an illicit "side door" to secure them admission.

Singer has not yet been sentenced after he pleaded guilty in 2019 to facilitating cheating on college entrance exams and using bribery to secure the admission of students to colleges as fake athletic recruits.

While Singer became a star government cooperating witness, prosecutors on Friday said they do not expect to call him to testify.

Prosecutors say Aziz, 62, agreed in 2018 to pay $300,000 to secure his daughter's admission to USC as a basketball recruit by bribing an official.

Prosecutors allege Wilson, 64, in 2014 paid $220,000 to have his son falsely designated a USC water polo recruit and later sought to pay another $1.5 million to fraudulently secure spots for his two daughters at Stanford and Harvard universities.