(CNN)Before July 2015, few knew the term “sanctuary city.”

Fewer still had heard of Kate Steinle, a 32-year-old medical device sales representative living in San Francisco.
But those two topics have become closely linked since then. And the acquittal Thursday of an undocumented immigrant in her 2015 death became viral breaking news and set off a series of fiercely critical reactions from leading Republican voices across the .
    President Donald Trump called the verdict “disgraceful.” Attorney General Jeff Sessions said the death was “preventable” and said San Francisco’s sanctuary city policies were to blame. Breitbart News for a time on Friday morning focused the top nine stories on its homepage to the verdict, and the hashtag BoycottSanFrancisco became one of the top trending topics in the US on Twitter.
    Why was there such a big reaction to this young woman’s death? And how did a murder trial in California become one of the most important criminal cases of the year?
    Steinle’s case broke through to larger awareness because it touched on several hot-button issues that have recently come to prominence.
    And that story largely begins — as most in today’s era do — with Donald J. Trump.
    “For Donald Trump, we were just what he needed — beautiful girl, San Francisco, illegal immigrant, arrested a million times, a violent crime and yadda, yadda, yadda,” Steinle’s mother, Liz Sullivan, told the San Francisco Chronicle in September 2015. “We were the perfect storm for that man.”

    San Francisco immigration policy

    On July 1, 2015, Steinle was walking on a busy pier of the Embarcadero district in San Francisco when she was killed by a single bullet to the chest.
    The man arrested, Jose Ines Garcia Zarate, 45, was an undocumented immigrant from Mexico who had been deported from the US five times previously, according to officials.
    He might have been deported a sixth time for a drug-related warrant, as Immigration and Customs Enforcement requested an immigration detainer and that the agency be notified before he was released.
    But officials in San Francisco released Garcia Zarate from custody in April instead of turning him over to immigration authorities. San Francisco is a “sanctuary city,” a term that broadly refers to a city that in some way does not cooperate with federal immigration enforcement.
    At the time, though, the term “sanctuary city” was not well known. A Google Trends query shows the phrase was rarely searched — until a sharp spike in July 2015.

    Trump picks up the story

    Two weeks earlier, Trump had launched his presidential campaign by criticizing US border security, saying that Mexico was sending criminals and “rapists” to the US.
    The comments faced harsh criticism from leaders across the political spectrum. Sen. Marco Rubio, his opponent in the Republican primary, said his comments were “not just offensive and inaccurate, but also divisive.”
    Steinle’s killing came two weeks later. Trump’s first tweet about Steinle on July 3 was to offer his “heartfelt condolences” to her family. Less than an hour later, he directed his anger at Rubio.
    “.@MarcoRubio what do you say to the family of Kathryn Steinle in CA who was viciously killed b/c we can’t secure our border? Stand up for US.”
    In a statement at the time, Trump said Steinle’s shooting was further proof of the need for a border wall.
    “This senseless and totally preventable act of violence committed by an illegal immigrant is yet another example of why we must secure our border immediately,” Trump said in a statement. “This is an absolutely disgraceful situation and I am the only one that can fix it. Nobody else has the guts to even talk about it.”
    Talk about it he did. Trump repeatedly brought up Steinle’s case on the campaign trail. In his speech accepting the Republican presidential nomination, he said he was deeply affected by the stories of parents whose children were killed by undocumented immigrants.
    “My opponent will never meet with them, or share in their pain. Instead, my opponent wants sanctuary cities,” he said. “But where was the sanctuary for Kate Steinle?”
    Other Republicans legislators took his cue. This June, the House of Representatives passed “Kate’s Law,” a bill that would create harsher penalties for repeat illegal entry to the United States and would expand US law to pressure local cities to cooperate with federal immigration enforcement. The bill has since stalled in the Senate.

    The Steinle family’s wishes

    Lost amid the heightened debate about the case’s impact on immigration policy was, well, the evidence and arguments presented in court.
    Prosecutors said Garcia Zarate intentionally and recklessly fired into a crowd on the San Francisco pier that day, killing Steinle. But his defense attorney said the shooting was accidental and emphasized evidence that the bullet ricocheted off the ground and traveled about 80 feet before hitting Steinle.
    One of the defendant’s lawyers said the debate over immigration didn’t belong in the case.
    “From day one, this case was used as a means to foment hate, to foment division and to foment a program of mass deportation,” public defender Francisco Ugarte said after the verdict.
    In court, there was no mention of the defendant’s immigration status, or his past criminal convictions, or San Francisco’s immigration policy. Jurors were asked to decide the question: Was there evidence beyond a reasonable doubt that the shooting was intentional?
    Similarly, the widespread focus on Steinle’s case often had little to do with the family’s wishes.
    CNN’s Anderson Cooper asked Brad Steinle, Kate’s brother, whether he felt his sister was being used by Trump. “In a way, yes,” he said.
    “Sensationalizing it is not the route we would like to go,” he said. “If you’re going to use somebody’s name and you’re going to sensationalize the death of a beautiful young lady, maybe you should call and talk to the family first and see what their views are.”
    Trump did speak to the Steinle family after that, telling CNN he wanted to leave a period of grieving first.
    Even now, the Steinle family has continued to shy away from the spotlight, and have mostly spoken to John Diaz of the San Francisco Chronicle. The Steinles said they were not involved in “Kate’s Law” and did not know who named it after their daughter.
    They also said they were not opposed to sanctuary cities, although they thought San Francisco’s then-sheriff went about it the wrong way.
    “We just want to get this over with and move on with our lives, and think about Kate on our terms,” Jim Steinle, Kate’s father, told the Chronicle after the verdict. “Nothing’s been on our terms. It’s been on everyone else’s terms.

    Read more: http://edition.cnn.com/