When Shirley Ree Smith was convicted of killing her grandson in a Van Nuys apartment in 1997, “shaken-baby syndrome” was all the rage.

If a baby showed signs of bleeding in the brain, the “shaken” diagnosis was a go-to — and the last person to have been in the same room with the baby was the prime suspect.

But a few years later, around the turn of the century, scientists began to question…

… if a shaking motion can really burst something in the brain. Dr. John Plunkett wrote an extensive paper on what he considered to be an urban legend, arguing that shaken-baby symptoms “might not immediately follow the injury, and that there were other, accidental sources for one of the 'classic' signs of SBS.”

By 2006, Plunkett's theories had gained enough steam that the 9th U.S. Circuit Court of Appeals overturned Smith's conviction, citing insufficient evidence that the grandma had killed her grandson. After a decade behind bars, she was allowed to go free.

However, proving that the syndrome is still very widely accepted (including by the American Academy of Pediatrics), a U. S. Supreme Court judge ordered she return to jail late last year.

That's where Governor Jerry Brown stepped in — he commuted her sentence for good today, saying she won't have to go back to jail.

“From my review of the information before me, including materials from the Los Angeles District Attorney's Office, it is clear that significant doubts surround Ms. Smith's conviction,” says Brown in a statement.

That could include new findings that the L.A. County Coroner's Office revealed last month, including “the complete absence of bodily trauma, such as face trauma, grab marks, bruises, rib fractures or neck trauma” in Smith's seven-week-old grandson.

And it surely hasn't hurt that Smith's supporters have been pressuring the governor via online petitions, Facebook activism, etc.

PBS spoke with Smith last month about what it's like to “live in legal limbo.”

Watch “It's a Good Thing” on PBS. See more from FRONTLINE.

Watch “Finally Justice Was Served” on PBS. See more from FRONTLINE.

Watch “Free, But Not Really Free” on PBS. See more from FRONTLINE.

Here's what happened on the night of the “crime,” according to City News Service:

Smith and her daughter, Tomeka, were staying at Tomeka's sister's apartment, along with Tomeka's two older children. [Etzel Glass, the baby,] was put on a sofa to sleep, and his siblings and grandmother slept in the same room.

According to testimony at the trial, Smith awoke to find Etzel on the floor. She reportedly rocked him back to sleep and placed him on the couch.

About two hours later, Smith awoke again and found that Etzel had thrown up and had blood coming out of one nostril, and that he was unresponsive, according to the testimony.

That was enough to convict Smith of second-degree murder.

But thanks to the governor, her nightmare is finally over. Unlike Schwarzenegger, who used his commuting powers to grant favors to political pals, Brown has done a solid for Smith — and for science — by erring on the skeptical side of “shaken-baby.”

[@simone_electra / swilson@laweekly.com / @LAWeeklyNews]

LA Weekly