Zarate was acquitted of first- and second-degree murder, involuntary manslaughter, and assault with a semi-automatic weapon. Jurors did convict him of being a felon in possession of a firearm. Garcia Zarate said the shooting was an accident.
Zarate, a convicted felon who has been deported from the USA five times, was accused of fatally shooting the 32-year-old Steinle in July 2015 while she was walking with her father and a friend in San Francisco.
"San Francisco's decision to protect criminal aliens led to the preventable and heartbreaking death of Kate Steinle", Sessions said in a statement issued Thursday evening.
Jurors had to decide whether Garcia Zarate shot Steinle unintentionally or committed murder.
The jury seemed to have been convinced by defense arguments that Garcia-Zarate had no direct intention of firing the.40-caliber Sig Sauer pistol that he found that day on the waterfront, four days after it had been stolen from a U.S. Bureau of Land Management ranger's auto nearby.
Steinle's death put San Francisco and its "sanctuary city" policy in the spotlight, as Democrats and Republicans lashed out at city officials for refusing to cooperate with federal deportation efforts.
Steinle's death became a rallying cry for President Donald Trump and others, who have invoked the case in decrying sanctuary cities and promoting the construction of a border wall between the USA and Mexico.
A photo of murder victim Kate Steinle, right, is placed on an easel as her father Jim Steinle (second from left) prepares to testify about her murder during a hearing of the Senate Judiciary Committee on US immigration enforcement policies, on Capitol Hill in Washington on July 21, 2015.
"Today is vindication for the rights of immigrants", defense attorney Francisco Ugarte said.
He said the immigration status of defendant Jose Ines Garcia Zarate had no relevance to the case and the verdict was a correct reflection of what transpired.
"ICE knew that he had been deported five times", Mirkarimi has said.
Jose Ines Garcia Zarate had been deported five times and was wanted for a sixth deportation when Steinle was fatally shot in the back in 2015.
He said Americans should be asking a very important question: "What good comes out of a sanctuary city law?" Garcia Zarate didn't deny shooting Steinle and said it was an accident.
The sheriff's department released him a few days later after the district attorney dropped the marijuana charge, despite a USA request to detain him for deportation. The incident sparked a nationwide debate over sanctuary cities and later became a central theme of Donald Trump's campaign for president.
A jury has reached a verdict Thursday, Nov. 30, 2017, in the trial of Mexican man at center of immigration debate in the San Francisco pier shooting.
Before the shooting, Garcia Zarate had been released from a San Francisco jail despite a request by immigration authorities that he be detained for deportation.
President Donald Trump's son, Donald Trump Jr. responded to the verdict and tweeted out saying: "What a disgrace".