On 26 September 2018, 10 prominent US college sports figures were arrested in connection with a federal investigation into fraud and corruption. Specifically, the government alleged that business managers and financial advisers had bribed basketball coaches to secure business with NBA-bound players, and that a senior executive with Adidas had further conspired with them to funnel payments to high school players and their families in exchange for their commitment to Adidas-sponsored college sports programs.

The scandal – which ensnared the top NBA draft pick Deandre Ayton, hall of fame coach Rick Pitino and Kobie Baker, the associate athletic director at Alabama, one of the country’s premier talent factories – was a black eye for the NCAA, the keystone cops who style themselves as virtuous defenders of amateurism in college sports while reaping billions off the backs of student-athletes, the majority of them Black and quite economically disadvantaged. The extent of the scheme wasn’t fully understood until one of the schemers, a middle-aged moneyman named Marty Blazer, was turned into an FBI informant. “There’s a saying in law enforcement of being ‘half a cop’,” says true crime writer Guy Lawson, “when you’re the criminal but you start to think cops are cool. Marty became a motivated cooperator. He became an inventive one.”

Lawson’s latest nonfiction book, Hot Dog Money, is Blazer’s Goodfellas story – one largely told from Lawson’s one-on-one interviews with Blazer, Blazer’s diary entries from the time and more than two years of Lawson digging through troughs of legal documents. Rather than providing another ruling on Blazer, Hot Dog Money cross-examines the seedy culture that created him and still makes college sports the major American spectacle that it is.

The book’s title comes from Blazer’s term of art for the financial favors he traded for his own ends until his sentencing on multiple federal fraud charges forced his government cooperation. In the sporting press, Blazer was likened to Pacino’s Frank Serpico, the renegade cop who took down his flawed institution. In reality, Lawson found Blazer closer to Ray Liotta’s Henry Hill – a wise guy who’d still be living the high life if the music never stopped. Lawson – who also wrote The Brotherhoods (about two cops who worked for the mob) and War Dogs (about the stoner gun runners from Miami who inspired the film starring Jonah Hill and Miles Teller) – is as reliable a narrator as they come. “I didn’t go to school in America,” he says. “I grew up in Canada, Australia and England. I watch American sports the way you might watch Formula One.”

As Lawson tells it, Blazer didn’t set out to become the shady archetype best known to college sports fans as “the bag man”. He was a mid-level financial adviser making six figures trading stocks and bonds with a client roster that slowly grew to include select members of the NFL’s Pittsburgh Steelers. The story of William “Tank” Black, the powerful football agent indicted for running a Ponzi scheme fueled with Detroit coke money, sparked Blazer’s larger ambitions.

Blazer teamed up with an agent and recruited football players from Pennsylvania colleges with the aim of attaching himself to future pros. That’s where the “hot dog money” came in. Blazer didn’t just pass cash-filled envelopes under the table. He sent money home to players’ struggling families, supplied them with luxury cars, paid for lavish trips to Miami and Las Vegas, and comped their inevitable strip club binges. Sometimes he’d arrange to have girls flown in for parties closer to campus. “The girls are being trafficked, the kids are being trafficked,” says Lawson. “Forget morality, how do you even describe the decency of it all? This is what the swirling of a flushing toilet looks like.”

In a typical hot dog money scheme, a college player receives cash in the form of a forgivable loan with the understanding that the bagman’s aboveboard services will be retained once the player turns pro; depending on the player, the bagman can make his money back many times over in boring management fees. A proudly devoted husband and father of three, Blazer was more interested in helping his clients make the most out of a corrupt system and went the extra mile to look out for them, paying for information that could help clients avert potential disaster. In one memorable instance, he saved a player from marrying a stripper-prostitute who had been deployed by her pimp for an extortion plot. “Protecting my players from vultures and hangers-on was incredibly satisfying,” Blazer says in Hot Dog Money. “I felt good, intellectually.” Nevertheless: everything he did was against NCAA rules.

And while getting caught by the Securities and Exchange Commission was what ultimately forced Blazer to become a confidential government informant, his willingness to cooperate came from righteous impetus to reform a morally bankrupt industry that, as Lawson puts it, “is designed to deceive and exploit”. Even with experience, some kids are no less wise to the ruse. Last month Glen “Big Baby” Davis, a college star who played in the NBA from 2007 through 2015, was sentenced to a 40-month prison term after being convicted in federal court for participating in a scheme to defraud the league’s healthcare benefits plan. Davis, who maintains innocence (although he says he was advised not to testify in court), claims that he was taken advantage of by the very people he trusted to do right by him. “We’re already fighting six feet deep from where we came from,” Davis said in an interview with the Higher Learning podcast. “To say I’m going to jail for the injuries and things that I’ve been through is crazy to me.”

On 23 May, another date that will live in college sports lore, the NCAA announced it would allow schools to pay players directly – a departure from 100-plus years of tut-tutting that comes in the wake of a multibillion-dollar agreement to settle three pending federal antitrust cases. “It’s like a thief saying, ‘I’m only gonna steal 80% from you,’” says Lawson, further appalled by the institutional dedication to keeping players financially illiterate. The settlement, he adds, just buys the NCAA more time to avoid questions about why it doesn’t use its billions to do more to school student-athletes on money matters. “The Alabama associate athletic director who gets caught up in this case for taking money from Marty,” says Lawson, circling back to Kobie Baker, “one of his job descriptions was to teach Alabama’s many, many future professional athletes how to avoid bad business entanglements. The NBA has this financial literacy program they run for incoming rookies. It’s the equivalent of sending a kid into a workplace having given them an afternoon at kindergarten.”

Alas, just as with Henry Hill, Blazer doesn’t get his hoped-for ending. Even though his cooperation with law enforcement results in jail time for an Adidas executive, two associates and four college coaches, and prompts an NCAA dragnet into a dozen colleges, Blazer – who received one year of probation in exchange and was ordered to pay $1.6m in restitution to the clients he defrauded – comes away from the experience more disillusioned than ever. Blazer’s up-close observations of G-men at work led him “to respect them less and less, and then see them finally as a bunch of buffoons”, Lawson says. NCAA investigators, Blazer found, were even worse – ignorant and overwhelmed by the unscrupulous behavior within their remit.

On 10 January, Blazer died at age 53 – too soon to see the NCAA finally buckle under the weight of its own hypocrisy. But he certainly did enough to be remembered as better. Two days earlier, as his collaboration with Blazer was winding down, Lawson remembers Blazer feeling glum about his more colorful anecdotes being left out of the final draft. Never mind if that was the point of coming clean. “I told him at the beginning, Marty, if you stick with it and really commit, the payoff down the road is that you will really understand your life in a better way,” Lawson recalls. “You will have taken the time to put things in order and think through why you did things and you didn’t. He said, ‘You know what? I’m glad you said that because it really did happen. I really did learn a lot about myself.’”

• Hot Dog Money: Inside the Biggest Scandal in the History of College Sports is out now