The fatal police shooting of a man who ran toward a Lancaster police officer armed with a knife was justified, the Lancaster County District Attorney’s Office has ruled.

“The officer had no time or opportunity to do anything but run for his life and only resorted to lethal force when he confirmed an imminent threat to his life remained," District Attorney Heather Adams said in a statement.

The Sept. 13 shooting of Ricardo Muñoz, 27, happened outside the home that Muñoz shared with his mother after one of his sisters called 911 to report that her brother was being aggressive.

It prompted hundreds of protesters to gather outside the Lancaster Bureau of Police headquarters later that evening and into early-morning hours to decry the police response.

The body-camera video of the officer who responded showed Muñoz coming out of the house, then immediately running toward the officer as the officer ran away. The officer is then seen firing his gun at Muñoz several times. Included in the video was a still image of Muñoz holding a knife in his hand just before he was shot. (Warning: The video in this link is graphic.)

“Adams determined that the officer was clearly justified in firing four shots at Muñoz, as Muñoz chased him with a large knife — clearly presenting a threat to the officer’s life,” the statement said.

“Between four and five seconds elapsed from the time Muñoz emerged from a doorway, chasing the officer, to when the officer fired shots,” it said.

Muñoz was pronounced dead at the scene. The District Attorney’s Office said it was not releasing the name of the officer because the shooting was justified.

“Anytime an officer uses deadly force it is a traumatic and emotionally charged event in our community, and a life-altering tragedy for the families directly impacted by the use of force,” said Adams.

Michael Perna, an attorney for the Muñoz family, said Thursday that the family was dismayed by the decision.

“It was crystal clear that Ricardo had mental issues and he was having a mental breakdown and he needed medical attention,” Perna said, adding that his office would be conducting its own investigation and that the family may sue.

According to a 911 call made by the sister, which was played during a news conference held by Adams on Wednesday, the sister told a dispatcher that her brother had been “very aggressive” and punched the inside of a car, and that their mother needed help taking him to a hospital. She also said her brother had mental problems — that he had schizophrenia and bipolar disorder.

The sister called from her house, about a block away from her mother’s house on the 300 block of Laurel Street.

In the hours after the shooting, protesters gathered outside police headquarters. After midnight, police used pepper spray to disperse the crowd, and some protesters were arrested after they threw bricks through the glass doors of the station and at a nearby post office.