ENGLEWOOD, N.J. — With tinted windows, no signage and a slightly cracked brick facade, the small, nondescript building on an otherwise nondescript street in this New York suburb seemed unusually modest for a sports agency that had negotiated hundreds of millions of dollars in contracts for NBA players, including Kevin Garnett, Kyle Lowry and Serge Ibaka.

But Andy Miller viewed ostentatious offices as a waste of money, according to those who worked for him, so it was here — and not in the lobby of some high-rent Manhattan high-rise — where federal agents gathered one morning in September 2017.

When the FBI raided ASM, Miller’s agency, amid a then-sprawling Justice Department probe of the basketball black market, it prompted speculation Miller and others at his agency would soon join Adidas officials and assistant college basketball coaches already facing criminal charges. A few months later, Yahoo published images of documents the FBI took that day, spreadsheets that appeared to show ASM made payments to people close to dozens of former college basketball players.

More than a year and a half later, however, the Justice ­Department’s basketball investigation appears to have ended without producing a criminal charge against Miller or anyone else at ASM. It’s likely the only former ASM employee to face criminal penalties will be Christian Dawkins, the former ASM recruiter convicted of several felonies relating to trying to funnel money to top high school and college basketball players. And while Miller has unofficially retired as an agent for NBA players, his agency continues to operate, just under a new name.

How did Miller and the others Dawkins helped land new clients avoid charges? It’s a question that has persisted throughout the NBA agent community and angered those close to the individuals facing prison time for trying to pay college basketball recruits.

“It’s outrageous that a 22-year-old kid could be charged, prosecuted and off to prison based on things he did exclusively for his bosses,” said Steve Haney, Dawkins’s attorney. “It’s unthinkable. It makes no sense or logic on any level.”

Miller, through his attorney, declined to comment for this story.

A spokesman for the U.S. attorney’s office in the Southern District of New York, which oversaw the investigation, declined to comment. According to interviews with several NBA agents — some of whom formerly worked for ASM, all of whom spoke on the condition of anonymity — the theories of how Miller avoided prosecution fall along several lines.

Miller could be cooperating with prosecutors and providing evidence against others, but this theory appears the most unlikely. Attorneys close to the case believe the investigation is over and no one else will be charged.

More likely, some of Miller’s current and former colleagues believe, prosecutors didn’t have the same smoking gun evidence against Miller they did against Dawkins, whom the FBI had on wiretapped phone calls and videotaped sting meetings discussing paying people to steer recruits to specific colleges.

In the spreadsheets later published by Yahoo, the FBI had strong evidence of Miller overseeing an operation that paid college players and their family members and friends. But the legal theory underpinning the entire Justice Department investigation — that arranging these payments constituted fraud and victimized the schools these players attended — required evidence the payments were intended to influence a college commitment. In Miller’s case, the spreadsheets do not indicate any interest in where the players went to college, as long as they signed with ASM if they made it to the NBA.

“The model at ASM is pretty much consistent with, at least from my interpretation, the model of almost every agency that’s recruiting or signing NBA basketball players, which is to identify the talent as young as possible, sometimes as early as ninth grade; cultivate, ingratiate yourself with the family, the player, the handler,” Dawkins testified in May. “I don’t really think anything is wrong with paying players.”

On the stand over parts of two days in May, Dawkins summarized his career in the agent world. A Saginaw, Mich., native and son of a longtime high school and college basketball coach, Dawkins began working for ASM when he was 21. Dawkins previously had been working as a recruiter for International Management Advisors, a Cleveland-based financial services firm seeking to work with NBA players.

In 2016, however, IMA discovered Dawkins essentially had been double-dipping for several months, earning his $50,000 annual salary from IMA and traveling the country as a recruiter while actually steering players to sign with Miller, who also was paying him, according to a lawsuit IMA filed against Miller. The suit was settled, and no terms were made public.

Once on board at ASM, Dawkins displayed an ability to forge connections with people close to future NBA players. Among the players he helped recruit for ASM, according to Dawkins, were Fred VanVleet, Malik Beasley and Jarell Martin. Money usually was involved, he testified.

“And you and a number of employees, agents and attorneys, in fact, were breaking rules at ASM, would you agree?” a lawyer asked Dawkins at one point.

“Yeah. Everybody was paying players,” Dawkins replied.

Later, Dawkins was asked who provided the money he was using to try to land recruits.

“Everything that I did was ASM company money. I didn’t have any money to pay people,” he said.

“So Andy Miller had you do his dirty work for him. Would you say that’s true?”

“That’s fair to say,” Dawkins replied.

A few months after the FBI raid, Miller relinquished his certification with the National Basketball Players Association, which polices agent activity. While it long has been suspected that paying to land recruits is widespread, it violates NBPA rules and is grounds for the union decertifying an agent.

Miller has remained mostly out of the public eye since. His agency, meanwhile, continues to operate under a different name: YouFirst, the European agency that bought a stake in ASM in 2011. The agency continues to represent ASM’s former top clients — Kristaps Porzingis, Myles Turner and Ibaka — but does not appear to have landed any of the top picks in last week’s NBA draft.

Headquartered in Madrid, YouFirst represents more than 500 athletes and coaches, primarily in basketball and soccer, and does business in 10 countries, according to a 2014 Sports Business Day interview with company co-founder Juan Aisa.

According to three former ASM employees, YouFirst executives in Spain were well aware of Miller’s recruiting tactics, but it doesn’t appear to be a violation of NBPA rules to know your colleagues are paying recruits. The NBPA declined to comment for this story.

When Yahoo published the payment spreadsheets the FBI took from ASM, some of the pages contained words in Spanish. According to former ASM employees, this was because YouFirst accounting staffers in Madrid needed to approve of ASM’s expenses.

YouFirst officials in the United States and in Madrid have not replied to voice mails and emails over the past year, including another email and phone message this past week.

Last July, when a reporter walked into the old New Jersey office for ASM, two employees in their 20s were unpacking boxes. ASM signage still lined the office, along with signed jerseys of some of Miller’s most high-profile clients: Garnett, Lowry and Chauncey Billups.

One of the YouFirst employees — Josiah Pinto, who runs online marketing for YouFirst, according to his website — took down a reporter’s contact information and said he would pass it along, while declining to answer any questions about ASM.

“We’re not ASM anymore; we’re YouFirst,” Pinto said. “I’m sure you know the story.”