A Black man was shot and killed by police officers in Philadelphia on Monday afternoon (Oct. 27). Authorities say they were responding to a call about a man wielding a knife, which his family identified as 27-year-old Walter Wallace Jr.

According to the Philadelphia Inquirer, a social media video of the encounter showed Wallace walking toward officers. When shots are heard, the man appeared to be multiple feet away from the cops.

“Why didn’t they use a taser?” Wallace’s father said to the outlet. He added that his son struggled with mental illness and was on medication.

“Why you have to gun him down?” he said. Wallace’s father believes police shot his son at least 10 times.

A witness — Maurice Holloway — said that Wallace had been holding a knife and was standing on his porch when police arrived. Holloway said the officers immediately drew their guns and that Wallace’s mother had tried to shield him.

“I’m yelling, ‘Put down the gun. Put down the gun,’” Holloway recalled. “Everyone is saying, ‘Don’t shoot him. He’s gonna put it down; we know him.’”

“He turns and then you hear the shots,” he added. “They were too far from him; it was so many shots.”

Police spokesperson Sgt. Eric Gripp says the responding officers ordered Wallace to drop the knife and that he “advanced towards” them. After the cops fired “several times,” one of them drove Wallace to the Penn Presbyterian Medical Center, where he died. According to Gripp, investigators are currently reviewing body camera footage from the shooting. Both officers involved have been taken off street duty pending the investigation.

“My prayers are with the family and friends of Walter Wallace,” Mayor Jim Kenney said in a statement on Monday night. “I have watched the video of this tragic incident and it presents difficult questions that must be answered. I spoke tonight with Mr. Wallace’s family, and will continue to reach out to hear their concerns firsthand, and to answer their questions to the extent that I am able.”

Protests erupted across Philadelphia overnight. Authorities say at least one police car was set on fire and 29 officers suffered minor injuries. One officer was hospitalized with a broken leg after being hit by a pickup truck. According to the Inquirer, police detained 10 people overnight, who are set to be released pending possible charges of rioting or assaulting a police officer. Around 20 people were reportedly arrested in connection to looting around the city.

In a statement, City Council Member Jamie Gauthier called the shooting a “downright tragedy” and demanded that police release body camera footage from the incident.

“Had these officers valued the life of this Black man — had they treated him as a person experiencing mental health issues, instead of a criminal — we might be spared our collective outrage at yet another injustice at the hands of police,” Gauthier said.