Philadelphia CNN  — 

Protesters took to the streets and bands of looters broke into businesses for a second night after officers in Philadelphia shot and killed a Black man who was holding a knife in an encounter that city officials say raises questions.

One group marched peacefully for much of the night, chanting Walter Wallace Jr.’s name and saying, “Whose streets? Our streets.” But the protest turned violent near a police precinct when the large crowd encountered a handful of officers. Several people in the crowd threw rocks, light bulbs, or bricks at the police. One officer was injured, according to a CNN crew at the scene.

There was looting by other groups of people in another part of the city, according to a police tweet and video from a CNN affiliate’s helicopter.

Aerial pictures from affiliate KYW showed people looting a Foot Locker and others emerging from a Walmart with televisions and other items.

“The Philadelphia Police Department is requesting that all residents in the 12, 16, 18, 19, 24, 25, and 26th Districts remain indoors except when necessary,” the city’s office of emergency management tweeted. “These areas are experiencing widespread demonstrations that have turned violent with looting.”

Monday’s shooting of the 27-year-old Wallace, caught on cell phone video, draws fresh attention to fatal use of force by police following months of protests over how officers treat Black people. The shooting and violent protests – which left 30 officers injured – also sharpen the focus on the swing state of Pennsylvania a week before the presidential election.

Anticipating further unrest, state and city officials had requested help from the Pennsylvania National Guard, which will be mobilizing several hundred members, according to spokesman Lt. Col. Keith Hickox.

There were 91 arrests Monday

Mayor Jim Kenney said video of the shooting “presents difficult questions that must be answered.”

Outrage over the shooting in West Philadelphia set off protests by demonstrators wanting to know why less-lethal force wasn’t used. But police said the officers were not equipped with Tasers.

Monday night saw violence and looting, leading to dozens of arrests and the officers’ injuries, most the result of thrown objects. One officer was struck by a pickup and taken to the hospital with a broken leg and other injuries, police said.

Businesses were looted, and five police vehicles and one fire vehicle were vandalized, police said. Police Commissioner Danielle Outlaw said 91 people were arrested during the unrest, including 11 on charges of assaulting police and 76 for burglary.

Acting Commerce Director Sylvie Gallier Howard said the city did not ask businesses to close early Tuesday though some told officials they would do so voluntarily.

The Philadelphia District Attorney’s Office is investigating the shooting jointly with the police unit tasked with investigating officer-involved shootings.

District Attorney Larry Krasner said he had watched the cell phone video and what he saw was concerning. “I would have to agree with both the police commissioner and the mayor that it presents some very serious questions that need to be answered.”

Authorities said the officers were wearing body cameras. Footage has been reviewed by the mayor and police commissioner but has not been made public because it is part of an ongoing investigation, officials said.

Krasner said his office has received some of the footage, but is waiting on more.

Police officers secure the scene of a police-involved shooting that left a man dead on Monday.

Outlaw told reporters Tuesday afternoon that she could not commit to releasing body camera footage in the next 48 to 72 hours, but added that she will be transparent as to what can be released and when.

She said the officers involved did not have Tasers.

Union says officers did their jobs

Mayor Kenney and other leaders called for peace as they acknowledged the underlying source of the anger.

“Last night, we saw further evidence of the anguish of black and brown residents of our city who have struggled their entire lives under systemic racism,” he said.

Like Kenney, Outlaw acknowledged that the video “raises many questions.” She said she is fully committed to a complete investigation and that she “felt the anger of the community” when she visited the scene after the shooting.

Both officers involved in the shooting are now on desk duty pending an investigation, according to a law enforcement source. The officers have spoken with investigators and are expected to continue to have dialogue as the investigation proceeds, the source said. The DA indicated his office has not interviewed them yet.

The union that represents the officers defended them as “doing their job” and asked the “public for its patience” as investigators gather details of what happened.

What police say led up to the shooting

Walter Wallace Jr., here with his mother, was shot and killed by Philadelphia police officers.

Police said the incident started with a call about a man with a knife, KYW reported.

“Responding officers witnessed a male on the block. Immediately they noticed he had a knife in his possession and he was brandishing it, and waving it erratically,” Philadelphia police Sgt. Eric Gripp told KYW.

Cell phone video recorded from inside a nearby vehicle captured the final moments of the confrontation. Wallace first can be seen walking around parked cars, crossing into the street from one side across to the other.

A woman – who a family member and law enforcement source said was Wallace’s mother – appears to be trying to intervene to help him as two male police officers in the street point their guns at him, the video shows. As Wallace comes around a parked car into the street, the two officers can be seen backing up as he walks towards them.

Multiple shots ring out as police fire, striking him. Sgt. Gripp told KYW that an officer took Wallace in his police cruiser to Presbyterian Hospital, where he died.

One witness, Maurice Holoway, told KYW that he and others in the neighborhood had pleaded with Wallace to drop the knife and that he wishes the call to police didn’t lead to the man’s death.

“Shoot him in his leg, or not shoot him at all,” Holoway said.

This video still shows a fatal police-involved shooting Monday in West Philadelphia.

JaHiem Simpson, who took the video of the police shooting, told CNN there was some commotion and arguing before police were called.

When police arrived at the man’s house, Simpson said a person who he later was told was Wallace’s mother told police that Wallace had mental health issues.

Simpson said Wallace exited the house about 15 seconds later with a knife. Everybody around him, according to Simpson, was telling him to put the knife down.

Simpson said he saw officers pull their guns as soon as they saw the knife.

“All I’m thinking in my head is, ‘Where the Tasers at?’ ” Simpson told CNN.

After the shooting, Simpson said everyone started yelling at the police officers, and more officers then came to the scene.

Simpson said he is most bothered that Wallace was shot right in front of his mother.

“How would you feel?” he asked.

Wallace’s uncle, Rodney Everett, 63, said his nephew was a “good-natured person.”

“I’m just disappointed that his life ended like it has. I don’t think it’s right. I don’t think it’s right at all. I don’t think they did any justice,” he said.

Everett said his sister, Wallace’s mother, is “balled up in pain.”

“We all are. But this right here, I know it’s hurting her. I’m just disappointed. This has got to stop.”

Wallace was an aspiring rap artist, his family told CNN.

Police union asks for patience during investigation

A police officer lies on the ground before being loaded into an ambulance on 52nd Street early on October 27.

Fraternal Order of Police Lodge #5 President John McNesby defended the officers involved.

“Our police officers are being vilified for doing their job and keeping the community safe, after being confronted by a man with a knife. We support and defend these officers, as they too are traumatized by being involved in a fatal shooting,” he said in a statement.

“We ask the public for its patience as investigators work to gather all the facts of this tragic incident in West Philadelphia. Our thoughts and prayers are with these police officers who had to use lethal force to keep themselves and the community safe.”

Top city leaders vowed to stay in touch with Wallace’s family as the investigation proceeds.

“I … will continue to reach out to hear their concerns first-hand, and to answer their questions to the extent that I am able,” Kenney, the mayor, said. “I look forward to a speedy and transparent resolution for the sake of Mr. Wallace, his family, the officers, and for Philadelphia.”

“Everyone involved will forever be impacted,” said Outlaw, the police commissioner, “I will be leaning on what the investigation gleans to answer the many unanswered questions that exist.”

CNN’s Mark Morales reported from Philadelphia and CNN’s Steve Almasy and Eric Levenson reported and wrote from Atlanta and New York, respectively. CNN’s Christine Sever, Rob Frehse, Paul P. Murphy, Mirna Alsharif, Kristina Sgueglia, Ganesh Setty and Meridith Edwards contributed to this report.