SAN FRANCISCO (CBS/AP) — A state appeals court has overturned a criminal conviction for weapons possession for Jose Ines Garcia-Zarate, who was previously acquitted of the murder of Kate Steinle in San Francisco in 2015.

The ruling by three judges in the First Appellate District found that the trial court failed to instruct the jury on a legal defense for Zarate, that he possessed the gun too briefly to be convicted of possessing a firearm as a felon.

Public defender Matt Gonzalez, who argued the case before the jury, said the improper instruction meant that Garcia-Zarate did not get a fair trial.

“This really wasn’t a close call. We were entitled to the instruction, and we should’ve had it. We thought that Mr. Garcia-Zarate would have been acquitted had the jury been instructed this way, so this is very gratifying for us,” he said. “He picked up an object not knowing what it was, it fired, and he threw it to the ground when it did fire.”

Zarate had been tried for murder in the July 1, 2015, shooting of Steinle, who was walking with her father and a family friend on Pier 14 off The Embarcadero. Zarate’s defense attorneys argued that he had picked up an object wrapped in rags, which he realized was a gun only when it discharged, hitting Steinle in the back.

Zarate was acquitted of the murder. After that, prosecutors filed the weapons possession charges and Zarate was found guilty and sentenced to three years in prison.

The gun had been stolen from a U.S. Bureau of Land Management agent’s car.

The case became a national flashpoint in debates over immigration, as Zarate is an undocumented Mexican citizen who had been deported five times and had seven felony convictions.

The case was frequently cited by President Donald Trump as he sought more restrictive immigration policies.

After the acquittal in 2017, Trump called the verdict in “disgraceful” in a tweet, and former U.S. Attorney General Jeff Sessions blamed the sanctuary city policy for Steinle’s death.

A statement released Friday night by the San Francisco Police Officers Association said that again Steinle and her family have been victimized by judges who are protecting criminals.

“This is yet another disgusting injustice perpetrated by a broken criminal justice system that is more intent on re-harming victims of crime and their families than holding violent offenders accountable,” Tony Montoya, president of the police officers association said.

Zarate remains in custody facing federal gun charges, according to the association.

Tony Serra, the attorney who is representing Garcia-Zarate on federal charges, said the state reversal means the district attorney will have the option of re-trying Garcia-Zarate on the gun charge.

“That kind of error causes reversals all the time. Then the prosecution has the prerogative of going again,” Serra said. “It’s going to be a big potential decision on what they’re going to do.”

Gonzalez said in a typical case it would not be likely for prosecutors to retry a defendant on a charge for which he cannot serve any more jail time, but “given the political nature of the case, it’s anybody’s guess as to what they will do.”

The San Francisco district attorney’s office was weighing its options, spokesman Alex Bastian said. The state attorney general’s office, which argued the case on appeal, also said it was reviewing the case Friday

© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press and Bay City News contributed to this report