Ted Leonsis was told a movie about the rape of Nanking -- when Japanese forces invaded the then-capital of China in 1937, killing hundreds of thousands and raping an estimated 20,000 women -- would be "too hard to see theatrically."

Leonsis, the owner of the NBA's Washington Wizards and the NHL's Washington Capitals, decided to make a movie about it anyway. He’s the producer of "Nanking," one of the strongest documentaries at Sundance this year.

Directors Bill Guttentag and Dan Sturman mix survivors' interviews, archival footage and readings of letters and memoirs by such actors as Mariel Hemingway, Woody Harrelson, John Getz and Jurgen Prochnow. The movie chronicles not only the atrocities committed by Japanese troops, but the work of Westernes (mostly U.S. missionaries and Nazi businessmen) who saved some 250,000 refugees.

Leonsis said at a Q-and-A Wednesday he was struck at the enormity of the Nanking atrocities during a Wizards game. He looked at the crowd at the Verizon Center and said to his wife, "This is how many people were raped in one month."

Leonsis isn’t the first NBA owner to go into movies. Utah Jazz owner Larry H. Miller owns the Megaplex Theatres and bankrolled the three "Work and the Glory" movies, and Dallas Mavericks owner Mark Cuban has gone big into movies -- as owner of Magnolia Pictures, the 2929 Entertainment production company, and a stake in the Landmark Theatres chain.