'Brainiac' Who FBI Says Was Hired To Take Tests For Rich Kids Revealed

LOS ANGELES (CBSLA)  -- Part of the widening scandal over college admissions involves a man -- described as a brainiac -- who would take tests for the academically-challenged, bumping up their scores to new heights.

Mark Riddell was the go-to guy to help kids' improve their test scores. But the feds say he took "tutoring" to the extreme -- often taking the test for the student. He was based in Florida, but the feds said he would routinely fly to Los Angeles when needed and it appears in 2015, when his wife had their baby and he was applying to grad school, he was needed a lot.

When you first see a photo of 36-year-old Riddell you can't help but notice the golden tan and big smile - and according to the feds he's also a really smart guy.

He worked at the IMG Academy, a college prep school near Tampa. His bio there claims he helped thousands of students gain admission to top colleges.

According to the 200-plus page indictment,  the alleged mastermind of the scheme, Rick Singer described Riddell to parents as his "best test-taker" and could "nail a score - he's that good."

Harvard-educated and a former tennis pro, Riddell could ace the SAT or ACT, according to federal investigators. For $10,000, they said he could almost deliver on the score the parents' wanted for their kids.

The indictment says "Desperate Housewives" star Felicity Huffman paid that $10,000 to bump her daughter's SAT score to a 1420 after she scored 400 points lower on the PSAT.

"I wouldn't even necessarily say just celebrities or just people who are incredibly wealthy, there are so many people whose expectations are just out of whack for what is right for their kids. And I feel like it does speak to this society we live in, which is a society that's obsessed with instant gratification," says local college admissions consultant Alexis White.

In many of the cases, the feds say students weren't aware the fix was in.

Riddell is apparently cooperating with the feds and is said to be hoping for leniency when he is sentenced.

Cruz says Riddell released a statement through his attorney that read, in part: "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. I understand how my actions contributed to a loss of trust in the college admissions process."

Riddell has been suspended from the IMG Academy. He has also agreed to plead guilty to mail fraud and money laundering.