LONG BEFORE AN October tweet in support of Hong Kong protesters spotlighted the NBA’s complicated relationship with China, the league faced complaints from its own employees over human rights concerns inside an NBA youth-development program in that country, an ESPN investigation has found.

American coaches at three NBA training academies in China told league officials their Chinese partners were physically abusing young players and failing to provide schooling, even though commissioner Adam Silver had said that education would be central to the program, according to multiple sources with direct knowledge of the complaints.

The NBA ran into myriad problems by opening one of the academies in Xinjiang, a police state in western China where more than a million Uighur Muslims are now held in barbed-wire camps. American coaches were frequently harassed and surveilled in Xinjiang, the sources said. One American coach was detained three times without cause; he and others were unable to obtain housing because of their status as foreigners.

A former league employee compared the atmosphere when he worked in Xinjiang to “World War II Germany.”

In an interview with ESPN about its findings, NBA deputy commissioner and chief operating officer Mark Tatum, who oversees international operations, said the NBA is “reevaluating” and “considering other opportunities” for the academy program, which operates out of sports facilities run by the Chinese government. Last week, the league acknowledged for the first time it had closed the Xinjiang academy, but, when pressed, Tatum declined to say whether human rights were a factor.

“We were somewhat humbled,” Tatum said of the academy project in China. “One of the lessons that we’ve learned here is that we do need to have more direct oversight and the ability to make staffing changes when appropriate.”

In October, Houston Rockets general manager Daryl Morey’s tweet in support of pro-democracy protesters led the Chinese government to pull the NBA from state television, costing the league hundreds of millions of dollars. The controversy continues to reverberate, as the NBA prepares to resume play this week after a 4 1/2-month hiatus because of the coronavirus pandemic. China Central TV recently said it still won’t air NBA games, and U.S. lawmakers have raised questions about the league’s business ties to China.

The ESPN investigation, which began after Morey’s tweet, sheds new light on the lucrative NBA-China relationship and the costs of doing business with a government that suppresses free expression and is accused of cultural genocide. It illustrates the challenges of operating in a society with markedly different approaches to issues such as discipline, education and security. The reporting is based on interviews with several former NBA employees with direct knowledge of the league’s activities in China, particularly the player-development program.

The program, launched in 2016, is part of the NBA’s strategy to develop local players in a basketball-obsessed market that has made NBA China a $5 billion enterprise. Most of the former employees spoke on the condition of anonymity because they feared damaging their chances for future employment. NBA officials asked current and former employees not to speak with ESPN for this story. In an email to one former coach, a public relations official added: “Please don’t mention that you have been advised by the NBA not to respond.”

One American coach who worked for the NBA in China described the project as “a sweat camp for athletes.”

At least two coaches left their positions in response to what they believed was mistreatment of young players.

One requested and received a transfer after watching Chinese coaches strike teenage players, three sources told ESPN. Another American coach left before the end of his contract because he found the lack of education in the academies unconscionable: “I couldn’t continue to show up every day, looking at these kids and knowing they would end up being taxi drivers,” he said.