SAN JOSE, Calif. (Reuters) - A former Stanford University swimmer whose six-month jail sentence for sexually assaulting an unconscious woman caused uproar was released from jail on Friday after serving half of his time.

Controversy over the short sentence for Brock Turner, a one-time U.S. Olympic hopeful, has stoked the intense debate about sexual assault on U.S. college campuses.

The case led California lawmakers to pass legislation to ban probation in similar assault cases and expand the definition of rape, and has set off an effort to recall the judge who handed down the sentence.

Turner, 21, left the Santa Clara County Main Jail in San Jose before dawn, three months after being jailed for assault with intent to commit rape, penetration of an intoxicated person and penetration of an unconscious person. Inmates can serve half time for good behavior.

Carrying a suit jacket and paper bag with his belongings, Turner walked silently from the jail and into a white sports utility vehicle that sped away.

His lawyer, Mike Armstrong, declined to comment on Friday. Court records show Turner expressed remorse over the assault and attributed his behavior to a night of drinking.

After his release, dozens of demonstrators gathered across the street from the jail to protest the short jail time and call for the removal of Judge Aaron Persky, who sentenced Turner in June.

“Why am I so passionate? I have a 16-year-old daughter,” San Jose resident Bonnie Montgomery said at the protest. “She’s going to college next year and I want her to be safe.”

A harrowing letter from the victim, who remains anonymous, helped draw attention to the case. She detailed the assault outside a fraternity house in January 2015 in graphic terms.

Turner, 19 at the time, was arrested after two students saw him on top of an unconscious woman near a dumpster.

Turner is expected to return to his parents’ home in Sugarcreek Township, Ohio. Greene County Sheriff Gene Fischer said Turner must register there as a sex offender if he moves in with his parents and would have to check in with authorities every three months for life.

He was charged with sexual assault instead of rape because although he digitally penetrated the woman, he did not have intercourse with her, and California law does not define that as rape.

Prosecutors had asked Turner be given six years in state prison.

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“If we had our way, Brock Turner would be in state prison serving a six-year sentence, not going home,” Santa Clara County District Attorney Jeffrey Rosen said.

Persky sentenced Turner to only six months in county jail and three years probation, following recommendations from a probation report that described the case as “less serious due to the defendant’s level of intoxication.”

In the wake of outrage and the recall effort, Persky last month asked to be assigned to the court’s civil division.

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California lawmakers passed legislation, which must still be signed by Democratic Governor Jerry Brown, that would bar probation in similar cases.

Lawmakers also passed a bill that would expand the definition of rape.

(This story has been refiled to correct spelling in byline to Cassie Paton from Cassie Patton.)