In a stunning California appeals court decision on Friday, the lone conviction in the case of Kate Steinle’s 2015 shooting death at the hands of an illegal immigrant in San Francisco was overturned.

Seven-time convicted felon Jose Inez Garcia-Zarate, in the U.S. illegally and previously deported five times to his native Mexico, was acquitted in November 2017 of first- and second-degree murder, involuntary manslaughter, and assault with a semi-automatic weapon. He was convicted of one count of being a felon in possession of a firearm, but that verdict is now reversed.

The reason for the reversal given by the 1st District Court of Appeal in San Francisco is that the judge had failed to advise the jury of one of Garcia-Zarate’s defenses. The jury should have had the option of acquitting him using the theory that he only possessed the firearm momentarily.

According to Fox News, prosecutors argued before the Court of Appeal “that the jury instruction lapse was harmless because Garcia-Zarate admitted firing the gun and experts said he couldn’t do so without pulling the trigger. The court disagreed, saying the jury’s verdict showed they rejected the prosecution theory that the shooting was intentional or even negligent and they had asked the judge to define possession and whether there was a time requirement for possession.”

“These questions go to the heart of the momentary possession defense,” Justice Sandra Margulies wrote in the unanimous 3-0 decision. “The fact the jury asked whether there was a time requirement for possession suggests jurors were wrestling with how long [the] defendant had the gun.”

Garcia-Zarate remains in custody, facing federal charges of firearm possession and being in the United States illegally. Tony Serra, his attorney, told The Associated Press that trial is scheduled to begin Jan. 13, adding that the appeals court reversal will give prosecutors the option to re-try Garcia-Zarate.

As for whether the state will re-try the murder case, the San Francisco district attorney’s office is weighing its options, according to spokesman Alex Bastian.

“That kind of error causes reversals all the time,” said Serra. “Then the prosecution has the prerogative of going again. The state case is a heavier case because it’s a homicide and a gun. … It’s going to be a big potential decision on what they’re going to do.”

Watch a local Bay area report on the decision:

Video by KPIX CBS

The Steinle case is an ongoing point of outrage over the justice system, the broad issue of illegal immigration, and sanctuary city protection of criminals.

BREAKING: California appeals court overturns sole conviction in Kate Steinle death CA has decriminalized illegal alien crime. This is sickening https://t.co/BzvQroU36p — John Cardillo (@johncardillo) August 31, 2019

Ken Cuccinelli, USCIS acting director, angrily tweeted: “Kate Steinle was tragically killed because San Francisco proudly proclaims itself a sanctuary city. How many more innocents will die b4 sanctuary cities stop harboring violent criminals? This defies common sense, public safety, & human decency.”

Kate Steinle was tragically killed because San Francisco proudly proclaims itself a sanctuary city. How many more innocents will die b4 sanctuary cities stop harboring violent criminals? This defies common sense, public safety, & human decency. #NoJustice https://t.co/rFeungS0wK — USCIS Acting Director Ken Cuccinelli (@USCISCuccinelli) August 31, 2019

The 32-year-old Steinle was killed July 1, 2015, after being struck by a bullet while she was walking with her father and a friend on a San Francisco pier. Garcia-Zarate was arrested, and claimed that he came across the stolen firearm wrapped in a T-shirt and that it went off accidentally.

Earlier in 2015, Garcia-Zarate was released from custody after a drug case against him was dropped. Due to the city’s sanctuary policy, the San Francisco sheriff’s office ignored a request by federal authorities to hold Garcia-Zarate until they could assume custody. They did not inform immigration officials that he was being released.