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Atlanta Hawks co-owner Bruce Levenson said Sunday he is selling his controlling interest in the team, in part due to an inflammatory email he said he wrote in an attempt "to bridge Atlanta's racial sports divide."

Levenson said he regrets the email sent to the team's co-owners and general manager Danny Ferry two years ago as "inappropriate and offensive." In a statement released by the team, Levenson said he sent the email due to his concerns about low attendance and a need to attract suburban whites.

He says he later realized the email made it seem white fans were more important. He voluntarily reported the email to the NBA.

"I have said repeatedly that the NBA should have zero tolerance for racism, and I strongly believe that to be true," Levenson said in the statement. "That is why I voluntarily reported my inappropriate email to the NBA.

"After much long and difficult contemplation, I have decided that it is in the best interests of the team, the Atlanta community, and the NBA to sell my controlling interest in the Hawks franchise."

NBA Commissioner Adam Silver said Sunday the league will work with the Hawks' ownership group and CEO Steve Koonin, who now will oversee all team operations.

Silver said the league's independent investigation "regarding the circumstances of Mr. Levenson's comments" in the email was ongoing. Silver said he was told Saturday night of Levenson's plan to sell his share of the team.

Silver said he supported Levenson's decision.

"As Mr. Levenson acknowledged, the views he expressed are entirely unacceptable and are in stark contrast to the core principles of the National Basketball Association," Silver said. "He shared with me how truly remorseful he is for using those hurtful words and how apologetic he is to the entire NBA family -- fans, players, team employees, business partners and fellow team owners -- for having diverted attention away from our game.

"I commend Mr. Levenson for self-reporting to the league office, for being fully cooperative with the league and its independent investigator, and for putting the best interests of the Hawks, the Atlanta community, and the NBA first."

Levenson is the second NBA owner to become involved in a racially charged controversy this year. Donald Sterling was forced to sell the Los Angeles Clippers after a recording surfaced in April of the owner scolding his girlfriend for bringing black men to Clippers games.

In the email sent in August 2012, Levenson shared his observations of the fan experience at Hawks games. He said he concluded "southern whites" were uncomfortable at games.

"My theory is that the black crowd scared away the whites and there are simply not enough affluent black fans to build a significant season ticket base," Levenson said in the email released Sunday by the Hawks.

"Please don't get me wrong. There was nothing threatening going on in the arena back then. I never felt uncomfortable, but I think southern whites simply were not comfortable being in an arena or at a bar where they were in the minority."

Levenson said Hawks crowds were 70 percent black, the team's cheerleaders are black and hip-hop music was played.

"Then I start looking around at other arenas," Levenson said. "It is completely different."

According to the U.S. Census Bureau, Atlanta's population was 54 percent black and 38.4-percent white in 2010. For metro Atlanta, the ratio is 55.4 percent white and 32.4 percent black.

Levenson said he often heard fans say the area around Philips Arena in downtown Atlanta is dangerous.

"This was just racist garbage," Levenson said. "When I hear some people saying the arena is in the wrong place I think it is code for there are too many blacks at the games."

Though he said he disagreed with the conclusion, he said he told team executives to add white cheerleaders and music "familiar to a 40-year-old white guy."

Added Levenson in the email: "I have even (complained) that the kiss cam is too black."

The Rev. Al Sharpton released a statement Sunday encouraging Silver "to continue vetting all owners."

"The announcement by Bruce Levenson is welcomed and appropriate by those of us in the civil rights community, that raised the issue of Donald Sterling's need to be removed, and that other owners must be held accountable," Sharpton said.

Though the NBA investigation of the email was ongoing, Levenson apparently concluded he couldn't continue in his ownership role.

"If you're angry about what I wrote, you should be," Levenson said in Sunday's statement. "I'm angry at myself, too. It was inflammatory nonsense. We all may have subtle biases and preconceptions when it comes to race, but my role as a leader is to challenge them, not to validate or accommodate those who might hold them."

This is not Levenson's first effort to sell the team. In 2011, the Hawks' ownership group, headed by Levenson and Michael Gearon Jr., made an unsuccessful attempt to sell to California developer and pizza chain owner Alex Meruelo.

Meruelo was introduced as the new owner at a news conference, but the sale later fell through. Levenson then announced the team no longer was on the market.

The group acquired the Hawks and the NHL Thrashers from Time Warner in 2004. The Thrashers were sold and moved to Winnipeg in 2011.