A 14-year-old girl was shot and killed on Thursday (Dec. 23) by Los Angeles police officers who were firing at an assault suspect. According to NPR, the incident occurred on Thursday morning at a Burlington store in San Fernando Valley’s North Hollywood area.

Witnesses told KCBS-TV that a man in the store began acting erratically, threatening to throw store items from the building’s upper floor and attacking a female shopper with metal bike lock.

Police say they responded to a report about an assault and shots fired at the store. However, a gun was not found at the scene. Officers opened fire on the man and a bullet went through a wall, striking the teenage girl, who was in a changing room with her mother. The assault suspect was also shot and died at the scene.

“This chaotic incident resulting in the death of an innocent child is tragic and devastating for everyone involved,” Police Chief Michel Moore said in a statement Thursday night. “I am profoundly sorry for the loss of this young girl’s life and I know there are no words that can relieve the unimaginable pain for the family.”

The chief promised a “thorough, complete and transparent investigation” into the shooting and said a recording of the 911 call, body camera video and other important footage will be released to the public by Monday (Dec. 27).

The assault victim, who chose to remain anonymous, was taken to a hospital and treated for moderate to serious injuries to her head, arms and face, the fire and police departments said.

The identities of the slain 14-year-old and her mother have also not been released, but investigators said they don’t believe the two shoppers were related to the woman who was attacked.

Along with the police department, the California Department of Justice is investigating the shooting.