What you need to know about the FBI's NCAA basketball investigation

— -- The U.S. Attorney's Office for the Southern District of New York announced federal corruption charges against four NCAA assistant basketball coaches on Tuesday.

The three-year FBI probe focused on coaches being paid tens of thousands of dollars to steer NBA-bound players toward sports agents, financial advisers and apparel companies.

Here's what we know regarding the federal probe into corruption and fraud in college basketball:

What are the charges?

As announced by U.S. Attorney Joon H. Kim at a news conference on Tuesday, federal authorities have brought forth two distinct sets of allegations.

Under the first group of charges, the U.S. Attorney is alleging that assistant coaches at Arizona, Auburn, Oklahoma State and USC "took cash bribes" in order to steer elite basketball players toward certain financial advisors and sports agents. The assistants named in the indictment are Chuck Person (Auburn), Emanuel Richardson (Arizona), Lamont Evans (Oklahoma State) and Tony Bland (USC).

Each of the coaches is charged with bribery conspiracy, solicitation of bribes, honest services fraud conspiracy, honest service fraud, conspiracy to commit wire fraud and Travel Act conspiracy. The U.S. Department of Justice said each of the coaches faces a maximum sentence of 80 years in prison.

In the second set of allegations, authorities say that James Gatto, on behalf of an unnamed "sportswear company," funneled "six-figure payments" to three players, who, in exchange, committed to play for particular college programs affiliated with the company. Gatto is the director of global sports marketing for Adidas.

This set of charges includes a reference to a "public research university located in Kentucky." University of Louisville interim president Gregory Postel confirmed in a statement that Louisville is the school mentioned.

Three of the four coaches were arrested Tuesday morning, along with James Gatto, director of global sports marketing for Adidas; Merl Code, another Adidas employee; Christian Dawkins, a former NBA agent; Munish Sood, a financial adviser; and two others.

Who is Marty Blazer?

In U.S. Department of Justice documents obtained by ESPN, Louis Martin "Marty" Blazer III is the witness who cooperated with the FBI in its investigation of the coaches and other defendants.

Blazer, a former Pittsburgh financial adviser who was accused of swindling $2.35 million from five clients by the Securities and Exchange Commission and founded Blazer Capital Management, was accused of investing money into movies and entertainment ventures without his clients' knowledge between 2010 and 2012. As part of his plea agreement with the U.S. Attorney's office, Blazer agreed to plead guilty to securities fraud, aggravated identity theft, false statements and documents, and two counts of wire fraud, according to the Sept. 19 cooperation agreement.

What is the scope of the alleged bribes?

The documents filed by prosecutors allege that the family of a "Player-10," former ESPN 100 recruit Brian Bowen, was to receive $100,000 from the "sportswear" company. The government also charges that Person received $91,500 from sports agents and/or financial advisors, of which he is said to have forwarded $18,500 to players and their families.

Could other programs or individuals face charges?

Yes. The FBI investigation is ongoing.

An FBI spokesperson at Tuesday's news conference warned others who could be involved in corrupt practices.

"We have your playbook," the spokesperson said. "... If you are involved in this, call us. It will be better for you to call us than for us to call you."

A phone number for a tip line was given at the news conference for anyone who wants to come forward with information.

Why is giving money to an assistant coach or young basketball player against the law?

The charges brought forward include violations of federal statutes on bribery and wire fraud, among other laws. Any assistant coach found to be taking bribes while employed by an institution receiving federal funds, for example, could be liable to prosecution under federal law.

What is the NCAA's reaction?

"The nature of the charges brought by the federal government are deeply disturbing," NCAA president Mark Emmert said in a statement. "We have no tolerance whatsoever for this alleged behavior. Coaches hold a unique position of trust with student-athletes and their families, and these bribery allegations, if true, suggest an extraordinary and despicable breach of that trust. We learned of these charges this morning and of course will support the ongoing criminal federal investigation."

The NCAA was made aware of the investigation on Tuesday as well.

Have the schools taken any action?

Yes. Auburn suspended Person without pay effective immediately.

Oklahoma State suspended Evans with pay.

Arizona suspended Richardson and relieved him of all duties.

USC placed Bland on administrative leave. USC also announced that it has hired former FBI director Louis Freeh to conduct an internal investigation.

In 2011, Freeh conducted an internal investigation of the Penn State child sexual abuse scandal involving Jerry Sandusky.

What happens next?

As noted at the news conference, the FBI is still pursuing its efforts but no longer doing so as a "covert" investigation. The phone number for the tip line is being prominently publicized, and no one can say how many more shoes will drop.

Speaking strictly in terms of college sports, the behaviors alleged by federal authorities constitute violations of NCAA bylaws.

According to official protocol, the NCAA notifies an athletic program that it is under investigation if the NCAA has found sufficient evidence. Then a series of hearings are held, often in front of the NCAA's Committee on Infractions. Lastly, after the NCAA renders its verdict and the program is given a chance to appeal, a final decision is handed down. This can be anything from a reduction in scholarships or a postseason ban on the basketball team to a show-cause order on a coach that prohibits him from being hired by any member institution for a stated number of years.

NCAA investigations can take anywhere from a few months to a number of years to reach a resolution. The NCAA's current investigation into alleged academic fraud at the University of North Carolina, for example, began in June 2014.

What about the head coaches at these programs?

The assistants charged by the authorities have larger concerns than their employment status right now. As for the head coaches that employed them, the first question will be whether any of the charged defendants will come forward with information directly implicating their head coaches.

Assuming no further information comes out documenting that head coaches had knowledge of what was taking place, much will depend on these coaches' previous track records in terms of compliance with NCAA rules, as well as the language on their current contracts. If the past is any guide, any terminations issued by university presidents could be made the subject of a wrongful termination suit by the head coach who was fired.