(Reuters) – A former Stanford University swimmer found guilty of sexual assault in California has appealed his conviction after serving a sentence that many condemned as an example of how the justice system fails to take such crimes seriously enough.

Brock Turner, then 19, was arrested in 2015 after two of his fellow students at the Northern California university saw him outside of a fraternity house on top of an unconscious woman. He was convicted of sexual assault the following year.

After serving three months of a six-month sentence, Turner was released early for good behavior. He had to register as a sex offender in his home state of Ohio last year, after leaving Stanford.

Turner’s lawyer, Eric Multhaup, said in papers filed on Friday in a California appeals court that a prosecutor in the trial incorrectly told jurors the sexual assault occurred behind a trash bin.

The woman Turner was convicted of sexually assaulting was found near a garbage enclosure but not behind a trash bin, according to the appeal. Multhaup said that implying otherwise gave the impression Turner tried to hide his activities with the woman.

The appeal comes as a surprise because political leaders, local residents and social media users had criticized Turner’s sentence as too lenient, rather than too harsh.

The 172-page appeal requests that the conviction be overturned and that Turner receive a new trial. But if he is convicted again, he could face a longer prison sentence.

In an email, Multhaup declined to comment beyond the court filing.

“Brock Turner received a fair trial and was justly convicted,” Santa Clara County District Attorney Jeff Rosen told the San Jose Mercury News. “His conviction will be upheld.”

The sentence the judge gave Turner stoked intense debate about rape on U.S. college campuses.

Santa Clara County Superior Court Judge Aaron Persky faces a recall effort over the six-month sentence he handed down.

Turner’s appeal also took aim at Persky, saying he erred by not instructing jurors to consider charges less serious than sexual assault and by not allowing testimony from character witnesses.

A representative for Persky could not be reached for comment.

Persky, in a statement on a website to fight the recall effort, said in his former career as a prosecutor he saw how sexual assault could destroy victims’ lives.

“When I became a judge, my role changed – I am required to consider both sides,” Persky said in the statement. “California law requires every judge to consider rehabilitation and probation for first-time offenders.”

In response to the Turner case, California lawmakers last year passed legislation to broaden the state’s legal definition of rape and mandate prison if the victim was unconscious.