The former Stanford University swimmer whose sentence for sexual assault has been widely condemned as too lenient spoke of drug and alcohol use before entering college, undermining his claims to a judge that he lacked experience with alcohol, court documents showed on Friday.

Brock Turner, 20, was sentenced by Santa Clara County Superior Court Judge Aaron Persky to six months in county jail after being convicted of sexually assaulting an unconscious woman. Prosecutors had sought a six-year term.

In a letter to the judge before his sentencing, Turner said he did not have experience with alcohol. "Coming from a small town in Ohio, I had never really experienced celebrating or partying that involved alcohol," according to court documents.