Thompson, who has a history of mental illness, could face a potential life sentence if convicted. San Francisco public defender Eric Fleischaker is representing Thompson, and his office said he may release a statement later on Friday.

Boudin, whose approach of stressing restorative justice over mass incarceration has come under fire, said he will prosecute the case himself, a move that the San Francisco Police Officers Association called a “political stunt”.

“The victims in this case and their families deserve the most experienced violent crime prosecutor in court today and not a criminal defence attorney with zero experience prosecuting any crime,” said Tony Montoya, president of the association, which opposed Boudin’s candidacy for district attorney,

A witness told KGO-TV that Thompson was carrying a large knife with knuckles on the handle and without warning attacked the women Tuesday as they waited for a bus on Market Street.

“The knife punctured one victim’s lungs, requiring extensive surgery,” the district attorney’s office said. “A knife had to be removed from another victim at the hospital.”

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Authorities initially said the women were 65 and 84 years old and did not immediately identify them. But a family member said the elder victim was 85-year-old Chui Fong Eng.

Victoria Eng said her grandmother was stabbed in the right arm, and the blade entered her chest. She underwent successful surgery.

“We were able to visit grandma today! It was so emotional walking in and seeing her,” Eng posted Thursday on a GoFundMe page that had raised more than US$98,000 to cover medical expenses. “The staff have been providing exceptional care to her and extremely supportive to our family. She wants to thank everyone for their generosity and well wishes!”

Some of the fundraiser money raised was offered to the family of the other victim, “but they politely declined”, the post said.

Both women were expected to survive, authorities said.

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Two Asian women attacked with hammer in New York after being told ‘take off your mask’

Two Asian women attacked with hammer in New York after being told ‘take off your mask’

Authorities haven’t said whether the women were targeted because of their ethnicity. But the District Attorney’s office said prosecutors were working with police to determine whether there was evidence to support hate crime allegations.

Police Chief William Scott initially said the attack appeared to be “totally random”.

Thompson was arrested in 2017 and sent to a state mental hospital after being found incompetent to stand trial in the stabbing of a man, the police association said.

In 2018, Thompson was sent into a state Mental Health Diversion programme that provides “intensive, court-monitored treatment and services,” the District Attorney’s office said.

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A judge allowed him to be released from the programme after nearly two years. He was not charged with any new offences. But he was arrested on warrants for missing court dates, including in April 2020, when he also was found to be in possession of a drug pipe, prosecutors said.

“What happened is a devastating tragedy, and we will use the full force of our office’s resources to prosecute this case. We also need to work hard to stop the next crime from happening, and that involves prevention and treatment,” the district attorney’s office statement said.

“Mr Thompson needed intensive supervision and services – which he received during Mental Health Diversion and which prevented new criminal behaviour.”

“We also must implement stronger responses to addressing the mental health crisis in our streets in order to keep our community safe,” the statement said. “For over 40 years, we have failed to invest resources into treatment, supportive housing, and other necessary services for those who are mentally ill and their families. We are all less safe as a result of that legacy.”