Philadelphia police shot and killed Walter Wallace Jr., a Black man who allegedly waved a knife in the street. Protests erupted into the night that injured 30 officers.

CNN reports the shooting occurred in West Philadelphia after officers responded to a “report of a person with a weapon.” Philadelphia Mayor Jim Kenney stated he saw the video and “it presents difficult questions that must be answered.” Kenney also spoke to the family of Wallace on Monday.

“I have directed the Officer Involved Shooting Investigation Unit to begin its investigation,” Philadelphia Police Commissioner Danielle Outlaw said in a statement. “I recognize that the video of the incident raises many questions. Residents have my assurance that those questions will be fully addressed by the investigation.”

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

In the video, a woman can be seen attempting to de-escalate the incident with the officers and Wallace as they cross in and out of the street and parked cars. As Wallace approached officers, they fired multiple shots. Wallace was taken to Presbyterian Hospital by an officer in his police vehicle only to, unfortunately, die from his wounds.

The killing and following protest occurred in what could be the most important swing state, Pennsylvania, just a week outside of the election. 30 officers were injured during the protests overnight, many by objects thrown. One officer is hospitalized after being hit by a truck resulting in her receiving a broken leg and other injuries. Multiple businesses were looted across the city.