It was a brutal crime: Four teens in San Francisco abducted a Golden Gate University student as she walked to her car, raped her over four hours, then dumped her on a desolate street, shooting her twice and running her down with her car.

The 24-year-old woman survived and testified in the 1981 trial of the teens. Three were 17 years old and one was 16 at the time of the attack, but they were prosecuted as adults, convicted of multiple crimes and sentenced to life in prison with the possibility of parole.

Thirty-six years later, one of the four, Michael Brown, has been freed under a California law that gives second chances to inmates serving life sentences who committed their crimes as minors or as young adults.

The rationale behind the law is that the prefrontal cortex of the brain, which controls impulse control, is still developing even into early adulthood. Research shows that this part of the brain isn’t fully developed until a person is in his mid-20s, and the law requires the state Board of Parole Hearings to give special consideration to inmates who committed their crimes before age 23 by weighing “the diminished culpability of juveniles as compared to that of adults.” In January, the state will extend the age to 25.

In Brown’s case, the parole board said at a June hearing that at the time of the crimes, he had a “17-year-old brain” and lacked impulse control. He became one of 900 prisoners to be freed under the youth-offender law since it took effect in 2014.

Most of the cases have sailed through the parole system with little notice since the law took effect nearly four years ago. But a handful of cases are flagged each year by Gov. Jerry Brown, a supporter of the law who nonetheless has objected to some of the parole board’s decisions.

Michael Brown’s case was one of them. The governor urged the parole board to reconsider its decision to free the former San Francisco resident.

The victim “experienced a night of horrors at the hands of Mr. Brown and his co-defendants,” the governor wrote in an Aug. 25 letter opposing Michael Brown’s release. “I’m not convinced Mr. Brown has confronted how he came to commit such a heinous crime.”

The San Francisco district attorney’s office also opposed the parole board’s decision, saying Michael Brown’s release posed “an unreasonable safety risk” to the public.

In September, however, the board stood by its decision and ordered the 54-year-old inmate freed from Folsom State Prison.

In 2014, the first year the youth-offender law was in effect, it applied only to inmates serving sentences of life with the possibility of parole who committed their crimes before they were 18. In 2015, the Legislature raised the age to 23, and in January it will go to 25 under a bill passed this year by Assemblyman Mark Stone, D-Santa Cruz. Stone said the law is meant to “align public policy with scientific research.” That research shows the brain undergoes a “rewiring” process that is not complete until a person is around 25 years old, and before that time the adolescent brain is “structurally and functionally vulnerable to impulsive” behavior, as peer-reviewed medical and science journals point out. That makes it difficult for a person to grasp the consequences of his actions at the time of the crime, supporters of the law said.

The law allows the inmates who are serving lengthy sentences to go before the parole board after serving 15 to 25 years and have that board strongly consider the age of the prisoner at the time of the crime.

“What we’re talking about are those who are able to be rehabilitated,” Stone said. “Those who we give the opportunity to set their lives in order after 15, 20 or 25 years in prison. They merely have the right to go before a parole board, ask that parole board for the possibility of parole.”

While 900 inmates have been paroled under the law, an additional 2,600 who have sought release have been denied — a number that supporters point to in arguing that the state isn’t being flooded with freed violent felons.

All three of Brown’s co-defendants have received parole hearings under the youth-offender law, but thus far have been denied. Their next hearings aren’t scheduled until 2021 and 2022.

“Many individuals who commit an offense when they are very young or young adults are able to change and grow and be rehabilitated, and if they make those changes they deserve a chance to be released,” said Maureen Washburn, a policy analyst at the Center on Juvenile and Criminal Justice in San Francisco.

But critics of the law, including some victims’ advocates and law enforcement groups, argue that the increased emphasis on an offender’s age when a crime was committed discounts other factors that contribute to a parole decision, such as the egregious nature of the crime or whether the prisoner is rehabilitated.

That’s what happened in the case of Michael Brown, said Christine Ward, executive director of Crime Victims Action Alliance.

“They brutally tortured this woman, shot her and ran her over. I mean, my God,” Ward said. “The ‘great weight’ put on the age of the inmate, it sounds nice when you think about it, but it has spun out of control at this point. We can’t just let people out because of their age.”

Michael Brown, Clyde Jackson and Larry Shepard were 17 and Damont Miller was 16 on Oct. 6, 1980, when they surprised the victim as she was unlocking her car on Second Street near Minna Street after attending night classes at Golden Gate University.

At their 1981 trial, the woman told jurors that the teens had pointed a gun at her, taken her car keys and shoved her in the back of her two-door Mercury Capri.

They drove to different locations in the city, raping her seven times and forcing her to perform oral sex on one teen while being raped by another. Jackson held the gun to the woman’s throat and told her they were going to dump her in the bay, she testified.

“I was in fear for my life,” she told the jury.

When she tried to grab the steering wheel, one of the men threw her from the car on a lonely patch of bayside land on Evans Avenue in the Bayview. There, Jackson and Shepard each shot her. One bullet struck her in the right wrist as she shielded her face and another struck her shoulder, she testified.

“I felt a burning sensation in my left shoulder,” she said. “One of them pointed the gun at my face. He fired a shot and I saw the car coming.”

When she tried to run, Shepard hit her with her car, sending her over over the roof and onto the ground, according to a summary of the incident in the governor’s letter asking for parole to be denied for Brown. After the car struck the victim, she said she pretended to be dead. When the car drove off, she ran to nearby homes and rang the doorbells until someone answered.

Then-District Attorney Arlo Smith prosecuted the four as adults and won convictions on 50 of 52 counts. Smith said in 1983 that the case pushed him to prosecute more youth as adults after one of the defendants, whom he did not name, suggested he would get a light sentence for the crime because of his age.

“I wanted to make it clear that anyone who engages in that kind of violence in this city will be tried as an adult and will be treated as an adult by the courts,” Smith said.

The state parole board refused to grant parole to Brown eight times before finally agreeing in June that he was reformed and ready to return to society. Two of the previous denials followed special youth parole hearings.

At the June hearing, Brown read a prepared statement: “I am sorry and deeply ashamed. Today, I truly understand the depth of (the victim’s) pain — not to mention the changes I have imposed on her life and her family, which I am sure has a long-term effect on how she sees people she meets.”

When questioned by the two commissioners on the parole panel, Brown said peer pressure had been partly to blame for why he took part in the attack on the woman. Board member Cynthia Fritz pressed him, noting he had been left with the victim alone at one point with a gun and that instead of letting her go, he had raped her.

“That bothers me every time, every time I think about that, why I didn’t let her go,” Brown responded.

He said that after one of the teens ran over the woman with her car, from his position in the back seat he could see her get up. “But I didn’t say nothing,” he said.

When Fritz asked whether he felt like he saved the victim’s life by keeping quiet, Brown responded, “Yes.”

He was convicted of kidnapping, robbery, rape and forced oral copulation. Because he did not shoot the woman or drive the car that ran her over, a jury had acquitted him of attempted murder and assault with a deadly weapon.

Besides his age at the time of the crimes, the parole board considered his nearly spotless prison record over the past two decades and participation in vocational programs. He received his general equivalency diploma in 1993, participated in self-help programs, including Narcotics Anonymous and anger management, completed vocational classes in cabinet making and janitorial maintenance, and worked as a landscape gardener at the prison.

Brown’s attorney, Kate Brosgart, told the board her client’s intellectual level in 1980 was below normal to the point of being “borderline retarded mental development.” She said Brown had been high on PCP and marijuana and had been drinking alcohol on the night of the crime, according to transcripts from the hearing.

San Francisco prosecutors, however, weren’t sold on parole. Representatives of District Attorney George Gascón’s office attended both the June hearing and a Sept. 19 session and each time argued that Brown was an “ongoing threat to harm society.” However, the parole board affirmed its decision to release Brown.

Brown’s victim did not attend the parole hearings, and The Chronicle’s attempts to reach her were unsuccessful.

Brown told the board he had no family on the outside to help him and was hoping to find transitional housing. Prison officials do not release information on where or when an inmate is released.

At the time of the crimes, Brown was new to San Francisco. He had moved from New York to live with his grandmother six months before he committed his crimes.

“Most of my family is deceased,” Brown said during his parole hearing. “Most everybody is gone. Grandma, Mas, Pops, Sis.”

He has no relationship with the siblings who are alive, he said.

“There’s going to be a lot of challenges going on in the streets because a lot of the way the world is now it’s a whole lot different. It’s cell phones and all that stuff going on,” Brown said.

But he said those challenges, along with entering a world in which he doesn’t know anyone, won’t push him back to drugs, alcohol or violence.

“That’s not going to happen,” he told the parole board. “I’m going to stay with some positive people that got jobs, that are doing good for themselves. I’ll never hang out with nobody that’s — that’s a lowlife.”

Melody Gutierrez is a San Francisco Chronicle staff writer. Email: mgutierrez@sfchronicle.com Twitter: @MelodyGutierrez