By Topher Gauk-Roger, CNN

(CNN) -- A White officer has been charged with felony manslaughter in the fatal shooting in April of a Black man in a Walmart store, a crime alleged under a newly strengthened California law that requires police to use deadly force only when needed to defend human life, the county prosecutor said.

San Leandro Police Officer Jason Fletcher, 49, was charged Wednesday with voluntary manslaughter in the shooting death of Steven Taylor, 33, after the pair scuffled over a baseball bat inside the store in the Northern California city, according to officials and court documents.

The charge comes amid intense nationwide scrutiny of police conduct following the death and severe injury of a string of Black men while in custody. California lawmakers last year enacted one of the strictest police deadly force measures in the country after a Sacramento prosecutor declined to charge two officers who killed Stephon Clark, an unarmed Black man, in his grandmother's backyard.

During the San Leandro confrontation, Taylor did not pose an immediate threat to police when Fletcher shot him to death, prosecutors determined, said Alameda County District Attorney Nancy O'Malley.

"The decision to file the criminal complaint was made after an intensive investigation and thorough analysis of the evidence and the current law," O'Malley said in a statement. "The work of Police Officers is critical to the health, safety, and well-being of our communities. Their job is one of the most demanding in our society, especially in these current challenging times. They are sworn to uphold and enforce the laws."

O'Malley cited the state legal standard that became effective January 1, noting its "intent is that peace officers use deadly force only when necessary in defense of human life. The legislature declared officers shall use other available resources and techniques if reasonably safe and feasible to an objectively reasonable officer."

Fletcher "was placed on leave after the incident and has been the entire time," San Leandro Police Chief Jeff Tudor told CNN on Thursday.

Fletcher's arraignment is set for September 15, she said. The officer's attorney and the San Leandro Police Officers Association did not immediately respond to CNN's requests for comment.

"As the Police Chief of San Leandro, I know the loss of Steven Taylor has deeply affected this community," reads a statement posted Wednesday from Tudor. "It is important that we allow the judicial process to take its course. I will refer all questions to the District Attorney's Office."

A deadly encounter of less than 40 seconds

Fletcher and another officer initially responded on the afternoon of April 18 to a report of an alleged shoplifter holding a baseball bat at the Walmart, according to a probable cause declaration cited by the district attorney's office. Taylor had been stopped by store security when he tried to leave without paying for the bat and a tent.

Fletcher didn't wait for his cover officer before heading over to Taylor in the shopping cart area, the police document reads. Fletcher tried to grab the bat from Taylor, it states, while pulling out his service pistol.

Taylor pulled the bat away, and the officer backed up. Then, from about 17 feet away, Fletcher drew his stun gun and pointed it at Taylor, the document reads.

"Officer Fletcher told Mr. Taylor to 'drop the bat man, drop the bat,'" the probable cause declaration states. "Officer Fletcher shot Mr. Taylor with his taser as he advanced towards Mr. Taylor. Officer Fletcher tased Mr. Taylor again, and Mr. Taylor clearly experienced the shock of the taser as he was leaning forward over his feet and stumbling forward.

"Mr. Taylor was struggling to remain standing as he pointed the bat at the ground," it continues. "Defendant Fletcher shot Mr. Taylor in the chest just as (a) backup Officer ... arrived in the store."

Taylor dropped the bat, turned away from Fletcher and fell to the ground, the police document says.

Less than 40 seconds elapsed from the moment Fletcher entered the store to when Taylor hit the floor, it reads. The cause of Taylor's death was a single gunshot wound to his chest, the Alameda County Coroner's Bureau confirmed.

Officer body-camera video released from the incident shows a confrontation, beginning with Taylor holding a bat near the store's entrance. In the video, Fletcher asks Taylor to put the bat down. When he refuses, Fletcher shoots Taylor with his stun gun. Taylor, still standing, stumbles closer to the officer, who then fires his pistol. Taylor falls to the floor.

A review of statements from witnesses and the officers involved, as well as a review of multiple videos shows that at the time of the shooting, "it was not reasonable to conclude Mr. Taylor posed an imminent threat of death or great bodily injury to Officer Fletcher or to anyone else in the store," a DA's statement reads.

"Mr. Taylor posed no threat of imminent deadly force or serious bodily injury to defendant Fletcher or anyone else in the store," it states.

Citing limited resources, California's attorney general declined the city's request to launch an independent investigation into the case, AG Xavier Becerra wrote to San Leandro City Manager Jeff Kay in a July 9 letter.

The city's request included references to ongoing internal investigations by the San Leandro Police Department, including an administrative investigation into compliance with internal department policies, procedures and tactics, plus an investigation into whether any crimes were committed and the district attorney's office's independent criminal investigation into potential charges for the officers, Becerra wrote.