Banned NBA owner Donald Sterling has hired four teams of high-priced private investigators to look for dirt on the NBA's dealings as part of his desperate plan to retain ownership of his Los Angeles Clippers franchise.

More specifically, USA Today Sports reports investigators will be looking for dirt on the league's former and current commissioners as well as the owners of the league's other 28 teams. The 81-year-old Sterling was banned for life from the league back in April after audio of him admonishing a girlfriend "not to bring black people to my games" was made public.

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According to USA Today, Sterling has bankrolled a budget over the next month where investigators will pore over the league's finances, allegations of previous discriminatory conduct and compensation to past Commissioner David Stern and current Commissioner Adam Silver.

"The gloves are off, as they say," a source told USA Today, adding investigators are also looking into whether or not other owners have made off-centered comments about race or sex over the last several years.

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Sterling has already sued the NBA for $1 billion, claiming league officials violated his constitutional rights by forcing him to sell his team based on information from "an illegal" recording. The league also fined Sterling $2.5 million for his transgressions.

Sterling's longtime spouse, Shelly, recently agreed to sell the team to former Microsoft exec Steve Ballmer for $2 billion, but Donald sterling is now also fighting that sale as improper and a four-day hearing on the matter has been set for sometime in July.