Hundreds of protesters filled the streets of Sacramento on Thursday, blocking traffic on a major highway and shutting down an arena after the police fatally shot a young black man in his backyard over the weekend.

A day earlier, the Sacramento Police Department released footage from body cameras and a helicopter that had recorded the chase and fatal shooting of the man, Stephon Clark.

Mr. Clark, 22, was living with relatives in a south Sacramento house when the police responded to a 911 call about a man breaking car windows and a glass door in the neighborhood. Assisted by a sheriff’s helicopter, they encountered Mr. Clark in the dark yard and fatally shot him, the police said.

He did not have a weapon. A cellphone was later found near his body.

The department, when it released the three videos and two audio recordings late on Wednesday, said the officers “believed the suspect was pointing a firearm at them.”