WALNUT CREEK (CBS SF/BCN) — The Contra Costa County District Attorney’s Office announced Friday that no charges will be filed against any of the officers involved in the 2019 fatal shooting of Miles Hall, a 23-year-old man experiencing a mental health crisis near his home.

Investigators in District Attorney Diana Becton’s office determined that there was insufficient evidence to prosecute Officers KC Hsiao and Melissa Murphy, who shot Hall a combined four times on June 2, 2019, after responding to reports of a disturbance at his home.

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At a news conference outside Walnut Creek City Hall on Friday, Hall’s family, their attorney and supporters expressed disappointment with the decision and renewed calles for accountability in the case.

“This whole process which we knew from the beginning, was extremely biased, was extremely pro-police,” said Gigi Crowder with the National Alliance of Mental Illness in Contra Costa.

The Rev. Wanda Johnson, the mother of Oscar Grant, who was fatally shot by a BART police officer in 2009 in a case that gained national attention, also spoke at the news conference.

“Our system of policing has to change drastically,” Johnson said.

Attorney John Burris, who is representing Hall’s family said, “Well you don’t talk to a mentally impaired person the same way you talk to someone else, in those circumstances.”

The shooting prompted Walnut Creek to pay a $4 million settlement to the Hall family and establish a series of listening sessions to discuss policing and public safety, Walnut Creek’s racial climate, and mental health issues.

(Courtesy: Justice for Miles Hall)

Hall’s shooting and the pace of the subsequent investigation led to public outcry and frustration over the lengthy process of local police reforms.

Miles’ mother Taun Hall initially made an emergency call to the California Highway Patrol around 4:40 p.m.

Other neighbors and witnesses made subsequent reports to law enforcement, claiming that Hall was carrying a nearly 5-foot long steel digging tool and chased at least one person’s vehicle on foot.

Walnut Creek police officers began arriving at the scene roughly 10 minutes later and set up a staging area near the intersection of Orchard Lane and Lancaster Road in an effort to intercept Hall.

Walnut Creek police officers had some previous knowledge that Hall dealt with mental illness after they had subdued him using non-lethal force during a previous encounter in which he had brandished a knife.

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Officers first attempted to contact Hall near 140 Arlene Lane, but he did not respond to commands to stop running and drop the digging tool.

Hall began running toward the officers with the digging tool in hand as Officer Matt Smith attempted to subdue him using a beanbag shotgun, according to the district attorney’s office.

Hall’s family has said that Hall subsequently changed directions in an attempt to run past the officers.

The beanbags did not slow Hall, at which point Hsiao and Murphy shot at Hall, hitting him four times. Hall was taken to John Muir Medical Center, where he was pronounced dead soon after.

“Because Mr. Hall was carrying 15 pounds of black steel digging tools, and he was carrying it in the direction of those officers, we believe that the evidence showed that there was not enough to file charges, that there was not a criminal act that occurred,” Scott Alonso of the Contra Costa County District Attorney’s Office told KPIX 5.

Following the settlement with the city of Walnut Creek, Hall’s parents said the money would be used to fund a foundation named after Hall that focuses on reforming law enforcement’s responses to people experiencing mental health crises.

The city of Walnut Creek’s budget for the current fiscal year also includes $100,000 to expand the use of mobile crisis units to respond to people experiencing mental health issues.

Walnut Creek Mayor Kevin Wilk said in a statement that the two years since Hall’s death have been painful and the city grieves over his death “each day.”

“Mental health is one of our society’s most serious crises and we must do whatever we can to provide immediate help to those who need it most,” Wilk said. “We will continue to work with the community to do whatever possible to prevent this type of tragedy from occurring again in Walnut Creek, and in the meantime we hope that all viewpoints are shared peacefully.”

Hall’s family said in a statement that they plan to call on California Attorney General Rob Bonta and U.S. Attorney General Merrick Garland to review the case.

“After nearly two long years of waiting anxiously for the conclusion of what we had hoped would be a thorough, unbiased, factually accurate investigation, we learned that there will be no justice and no accountability for the indefensible actions that resulted in our son’s death — at least not today,” the Hall family said.

Alonso, with the DA’s office, told KPIX 5, “The family can ask another prosecuting agency to get involved, so in this case it would be the State Attorney General’s Office. We would not oppose that and if they want to do that, that is certainly their right.”

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