A series of missteps were made at a Granada Hills group home for adults with developmental disabilities that led to the torturous slaying of a female resident earlier this year, a civil lawsuit claims.

Dawn Marie Ritz, 61, was allegedly stabbed in her bed more than 100 times by another resident who had obtained an unsecured kitchen knife at the Aacres adult residential facility in Granada Hills, according to the complaint filed on behalf of Ritz’s family last week in Los Angeles Superior Court.

The lawsuit, which names the Aacres facility in the 16500 block of Bircher Street, its overseer Embassy Management, LLC and the home’s administrator as defendants, also claimed that the two residents involved had been part of an ongoing dispute for months.

“We look at what happened and it looks completely preventable,” Attorney Gregory L. Johnson of the Johnson Moore law firm, which is representing Ritz’s family in the lawsuit, said Monday by phone. “The rules they needed to follow are so basic and simple for the safety of the residents.”

Neither an executive for Aacres nor a spokeswoman for Embassy Management responded to requests for comment Monday.

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Ritz, a former Special Olympics athlete, was stabbed to death in her bed allegedly by Ravneet Kaur in the early morning hours of May 14, according to Los Angeles police. Kaur, 18, pleaded not guilty to one count of murder in May and faces life in prison if convicted.

Kaur is currently going through the mental health court process to determine whether she is competent to stand trial, according to a spokesman for the L.A. County District Attorney’s office.

The dispute between the two residents began early this year when Kaur attacked Ritz “by hitting her over the head with a cup,” requiring her to get stitches, the complaint states.

While the facility’s administrator reported that incident to the Ritz family, she failed to report it to the California Department of Social Services’ Community Care Licensing, which licenses and regulates such facilities, the lawsuit alleges.

By May, the dispute was still continuing to the point where the facility’s staff was aware of the issue and the potentially dangerous situation brewing. However, they “failed to take affirmative steps” to ensure the argument didn’t escalate – or to adequately monitor the situation to protect both residents from harm, the complaint contends.

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On the morning Ritz was killed, according to the lawsuit, “staff were not awake and/or were not providing adequate supervision of the facility residents to intervene before Ms. Kaur gained access to a knife, which was supposed to be locked at all times, and before Ms. Kaur gained access to Ms. Ritz’s room and began repeatedly stabbing Ms. Ritz.”

The Aacres facility also failed to heed a warning from the state during a pre-licensing visit last year regarding the need to store its knives in a locked closest.

Instead, the facility “continued to store their knives in an unsafe manner setting the stage for the violent murder of Ms. Ritz,” the lawsuit alleges. “This was a completely preventable death.”

The caretaker on duty at the Aacres facility told Los Angeles police that she had locked the cabinet where the knives are stored on the night of the murder as required, but that somehow the suspect was still able to obtain a knife from the kitchen, Los Angeles Police Department Detective Steve Castro has said.

Once Kaur entered Ritz’s room and began stabbing her, the overnight caregiver could not enter the room right away once she heard the victim’s violent screams because it had been locked from the inside. The caregiver was finally able to pry open the door with a fork, authorities said.

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The lawsuit, which does not specify the amount plaintiffs are seeking, alleges dependent-adult abuse and neglect as well as wrongful death.

In addition to ensuring knives are locked up and that there are no locks on doors, Ritz’s brother Joseph Phelan of Meridian, Idaho said caregivers need to have the appropriate training and there should be monthly inspections of such facilities “so people don’t become complacent and not do their jobs properly.”

“I would like to see that her death not be in vain,” Phelan said by phone Monday.

His wife Sheryl Phelan added that more oversight is needed to prevent such tragedies from happening again.

The California Department of Social Services’ Community Care Licensing Division has yet to complete its own probe into the fatal stabbing, DSS spokesman Michael Weston said in an email.

That investigation will determine whether state regulations were being followed properly, whether there was appropriate care and supervision at the time of the incident and whether there was adequate staffing and the needs of the residents were being met.

Depending on the findings by the agency’s peace officer investigators, the facility could be cleared, cited, fined or eventually have its license revoked, according to the agency.