(CNN) -- The officer involved in the deadly shooting of a black man in September does not bear criminal liability and was legally justified to shoot, according to San Diego's district attorney.
"After carefully reviewing the facts, the evidence and the law, we've determined the officer's use of deadly force was reasonable under the circumstances," Bonnie Dumanis said in a statement.
Alfred Olango, 38, was fatally shot after he pulled a vaping device from his pocket and pointed it at police on September 27 in El Cajon, California.
His death set off demonstrations in the San Diego suburb as protesters demanded accountability. In her remarks, Dumanis acknowledged the case had sparked international attention and that the decision "will upset some in the community."
Dumanis nonetheless backed the decision, pointing out a thorough investigation that included witness accounts as well as cell phone and surveillance camera video footage of the incident.
In a comprehensive letter to the El Cajon Police Department, the district attorney detailed the events leading to the fatal shooting.
According to the letter, Olango's sister called the police to report her brother was behaving erratically on the street, almost getting struck by traffic, and requested he be taken to a mental health facility.
When officer Richard Gonsalves arrived at the scene, he asked Olango to remove his hand from his right pocket, while a second officer approached him with a Taser. Olango refused and then suddenly pulled a metallic object -- thought by the officers to be a gun but later discovered to be an electronic cigarette device -- and took a two handed shooting stance.
Gonsalves, a 21-year veteran of the force, fired four rounds, striking Olango fatally, as simultaneously the second officer fired his Taser.
According to Dumanis, the investigation showed Gonsalves had reason to believe he was in danger and his fear of being shot was reasonable.
"We're living in a time when the actions of police officers are under scrutiny more than ever -- especially when it comes to police shootings," Dumanis said. "The law recognizes police officers are often forced to make split-second decisions in circumstances that are tense, uncertain and rapidly evolving," she added.
The district attorney statement included updated statistics on officer-involved shootings that occurred in San Diego County over the past four years. The review shows that 27 of the individuals who were shot were white, 26 were Hispanic, five were black, and three were Asian.
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