William "Rick" Singer leaves the federal courthouse after facing charges in a nationwide college admissions cheating scheme in Boston, Massachusetts, U.S., March 12, 2019.

"I vividly remember him saying to me that, 'I've placed a number of kids,'" said the man, who spoke to CNBC on the condition of anonymity.

"When he was laying that down, he gave me the impression my kid wasn't the first kid" Singer had gotten admitted by such a ruse, said the man, adding that he never considered going along with Singer's suggestion.

"I think there was 90 seconds of asking about his grades and his SATs and his extracurricular activities, and then it shifted" into how to have his son win admission by pretending to be a water polo team recruit and making a "contribution" to the water polo team, recalled the man.

A man who talked to college admissions advisor William "Rick" Singer eight years ago about getting his son into a top California school says Singer matter-of-factly raised the idea of using fraud to make that happen — for a whopping $100,000 fee — less than two minutes after their conversation began.

The man noted that before their call, Singer did not know who he was.

Singer, 59, pleaded guilty Tuesday to federal criminal charges connected to his alleged widespread, $25 million scheme to help wealthy parents bribe, cheat and otherwise fraudulently game the college admissions system to gain entry for their children to highly ranked universities.

Prosecutors have charged TV actresses Felicity Huffman and Lori Loughlin in the scheme, along with Loughlin's husband, fashion designer Mossimo Giannulli. Other parents charged include PIMCO CEO Douglas Hodge, now-former Hercules Capital CEO Manuel Henriquez, top lawyer Gordon Caplan and investment fund CEO Bill McGlashan.

Also facing charges are college athletic coaches who were allegedly paid to falsely claim certain students would play sports that they actually never ended up participating in.

One of the California universities allegedly victimized in the scam was the school that Singer and the man who spoke with CNBC talked about getting the man's son into in March 2011.

The man who spoke with CNBC said that Singer, founder and CEO of the Edge College & Career Network, was referred to him by a friend whom he had talked to about his son's college admission efforts.

"He said, 'You should be in touch with this guy,'" the man recounted.

"He was pitched to me as a guy who packaged your kids" to apply to college, the man said.

The man said that when he spoke with Singer on the phone, the first minute or so of the conversation seemed appropriate. Singer asked questions about his son's academics and whether he had written a college application essay, the man said.

"You say, 'This is a college placement kind of guy,'" the man recalled.

But then Singer asked a question that seemed "weird," the man said.

"He asked me how tall my son was," the man said. "And then he asked me how much he weighed."

"Then it shifted ... he said, 'I can actually slot your kid into the water polo team,'" the man recalled. "I said, 'He never played.' He said, 'That's OK.'"

Singer told the man that as part of his $100,000 fee, a "contribution" would be made to the water polo team at the university the son wanted to attend. After his son gained admittance to the school, Singer told him, his son would either quit the water polo team or be cut from it, without ever participating in any team activity.

"The scheme was, 'Get him in, and then get him out,'" the man recalled.

Singer told the man "there's a sense of urgency here" because at the time they were talking it was the season for college placement.

After Singer detailed the proposed scam, the man told Singer, "I'll get back to you."

The man said he never called Singer back and they never spoke again.