SAN FRANCISCO (AP) — Attorneys for a Mexican man acquitted of murder in a San Francisco shooting that helped fuel the U.S. immigration debate are pressing for documents to help them argue that his U.S. gun charges are vindictive.

Federal prosecutors charged Jose Ines Garcia Zarate with two counts of illegal gun possession in November after jurors in state court found him not guilty of the 2015 killing of Kate Steinle on a popular pier.

Under San Francisco’s “sanctuary city” policy, the sheriff’s department released Garcia Zarate from jail several weeks before the shooting despite a federal request to detain him until immigration authorities could take him into custody. He was living in the country illegally and had been deported five times before the shooting.

Garcia Zarate’s attorneys, J. Tony Serra and Maria Belyi, said in a court filing Tuesday that the federal prosecution is an attempt to punish him for being acquitted in state court.

The charges are similar to a conviction that the San Francisco jury did return — being a felon in possession of a gun — that led to a three-year jail sentence. Garcia Zarate has pleaded not guilty to the two federal charges.

The attorneys cite tweets by President Donald Trump calling Garcia Zarate’s acquittal “disgraceful” and a “travesty of justice” as well as comments by U.S. Attorney General Jeff Sessions after the verdict that San Francisco’s immigration policies were to blame for Steinle’s death.

“This prosecution seeks to demonstrate to any high-profile defendant, especially one that is an undocumented immigrant, that their successful exercise of due process rights will not be respected and will result in the heavy hammer of a federal prosecution,” Serra and Belyi said in the filing first reported by Courthouse News.

California and the Trump administration have been in an escalating fight over immigration and other issues. The Justice Department has sued the state over laws aimed at protecting immigrants, saying they are hampering federal efforts to remove dangerous criminals.

An email to a Justice Department spokesman seeking comment was not immediately returned.

Garcia Zarate’s attorneys also accuse state and federal prosecutors of colluding on the case, violating the constitutional prohibition on prosecuting someone twice for the same crime.

They want a court order requiring officials to turn over numerous documents, including all communication directing the U.S. attorney’s office to convene a grand jury to pursue the federal charges against Garcia Zarate.