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Protesters on Tuesday denounced a Northern California prosecutor's decision not to file criminal charges against a sheriff's deputy who fatally shot a 13-year-old boy after mistaking the teen's pellet gun for an assault rifle.

Dozens of demonstrators rallied Tuesday outside the Sonoma County District Attorney's office, chanting "Justice for Andy Lopez" and wearing T-shirts with the eighth grader's image.

District Attorney Jill Ravitch announced Monday that her office cleared Deputy Erick Gelhaus of any criminal responsibility for shooting Lopez on Oct. 22 as the eighth-grader walked near his home in Santa Rosa.

Ravitch's report cited autopsy results showing that Lopez had smoked marijuana about an hour before the shooting, and a medical expert concluded the drug likely impaired the teen's judgment.

Gelhaus fired multiple rounds in response to what he believed was an imminent threat of death, Ravitch said at a news conference. She displayed photographs of the pellet gun found next to Lopez and a real assault rifle to highlight similarities in appearance.

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Gelhaus "believed honestly and reasonably that he was faced with a do-or-die dilemma," Ravitch said. "While it was absolutely a tragedy, it was not a criminal act."

Lopez's death have aggravated racial tensions in his mostly Latino neighborhood in the city of about 170,000 people north of San Francisco and led to large demonstrations to protest police brutality.

"Jill Ravitch essentially shirked her responsibility and provided all excuses possible for someone like Erick Gelhaus to get away with indiscriminate murder," said Ramon Cairo, a Santa Rosa resident who attended Tuesday's rally.

The parents of Andy Lopez said they felt they lost their son again and called Ravitch's decision "impossible" to accept.

"This disheartening decision leaves the family feeling as though Andy had been killed again today," Rodrigo Lopez and Sujay Cruz said in a statement released by their lawyer, Arnoldo Casillas.

Lopez's family has filed a wrongful death lawsuit filed in federal court in San Francisco against the county and Gelhaus, which has been on hold pending the outcome of the district attorney's investigation. Casillas said he will ask the court to restart the litigation.

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