WNBA Star Skylar Diggins-Smith, Yo Gotti Demand Justice in Attempted Lynching

WNBA superstar Skylar Diggins-Smith wants justice in her home state ... for the black man who's near-lynching was captured on video, so she's fired off a letter to U.S. Attorney General William Barr.

TMZ has obtained a copy of the letter Skylar and fellow Roc Nation client Yo Gotti sent to the Department of Justice regarding the case of Vauhxx Booker ... who was horrifyingly attacked over the Fourth of July weekend.

Video of the incident showed several white men pinning Vauhxx up against a tree and calling for someone to bring a noose for him. Passersby eventually intervened and convinced the men to release Vauhxx, and although state charges have been filed against the suspects ... Skylar and Gotti want the feds to get involved.

In the letter they write, "A violent racist racist attack such as this, additionally, is a federal crime." Additionally, they say the attempted lynching of Vauhxx, a civil rights activist, "demands your attention and your full efforts to guarantee that justice is done, by prosecuting the people who attacked Vauhxx Booker for their violent hate crime."

Skylar was born in South Bend, IN, and became a Notre Dame star hoops star. Both she and Gotti have enlisted Team Roc to throw some legal muscle -- attorney Joe Tacopina -- behind the fight to get justice for Vauhxx.