MINNEAPOLIS (AP) — Minnesota prosecutors say there will be no charges filed against Chinese billionaire Richard Liu, who was arrested in Minneapolis after a Chinese college student accused him of sexual assault.

Liu is founder of the Beijing-based e-commerce site JD.com. He was arrested Aug. 31 on suspicion of felony rape and released. He returned to China. Prosecutors said Friday that “profound evidentiary problems” would have made it “highly unlikely” that any charge could have been proven beyond a reasonable doubt.

Liu was in Minneapolis for a weeklong residency as part of the University of Minnesota’s doctor of business administration China program.

Liu’s attorneys have said he is innocent. JD.com has said he was falsely accused.

Liu is known in Chinese as Liu Qiangdong. He is worth $7.5 billion.