Who is responsible for insuring my mother's safety at her memory care facility?

Recently, a nurse at my mom's care facility called my sister to report that there had been an "incident" involving Mom and another resident. The other resident is an elderly lady with a horrible disposition. She constantly swears, shouts, throws objects, and takes swings at residents and caretakers alike. She even charges at visitors with fists raised, swearing and screaming at them. My sister and I have both been on the receiving end of these tirades. According to the nurse, my mother was sitting in a chair in the dining room when this woman had one of her temper tantrums. She grabbed my mother's throat from behind and was squeezing it, apparently trying to choke her. The dining staff called for help and they pulled the woman away, but not before she had injured my mother's throat and, when Mom tried to pry her hands off, she grabbed her arm and twisted it, injuring Mom's shoulder. The nurse made very light of it when speaking with my sister. I got a similar story about the incident from Mom, who called me. However, while the nurse told my sister that Mom was "fine," Mom said everyone was running to the woman and coddling her - only one person, the administrator, checked to see the extent of my mother's injuries.

I phoned the nurse, asking for an incident report. He said I wasn't entitled to one due to the HIPAA law protecting the attacker's health information! I asked that the woman be either moved to the other wing of the facility or discharged before she hurt Mom or other residents. He replied that this could not be done.

Now my sister and I are concerned about our mother's safety. If I cannot get an incident report or assurance that this woman will be more closely controlled in the future, should I file a police report or consult an attorney and press charges against the woman and the facility?