The family of slain Oakland, California, woman Nia Wilson is suing BART for negligence over her death, the East Bay Times reports.

The law firm representing Wilson’s family announced Wednesday that its plans to sue the San Francisco Bay Area transit system, saying that it had a legal obligation to keep the 18-year-old safe.

“BART has a legal duty to provide the highest care to protect its passengers from assault,” said Arns Law Firm attorneys Robert Arns and Jonathan Davis. “During a time when the incidence of violent crime in Oakland and the rest of Alameda County is decreasing, violent crime on BART is increasing. BART management has failed to come clean with the public about the dangers riders face every day.”

Wilson was stabbed and killed at the MacArthur BART station on July 22while she and her sisters waited on the train’s platform. John Lee Cowell was arrested in her slaying.  Her older sister, Lahtifa Wilson, was also stabbed but survived.

BART spokeswoman Alicia Trost told the East Bay Times in a statement on Wednesday that Wilson’s death was a “tragedy” and that the reason the suspect is in custody is because of BART’s camera system.

“The murder of Nia Wilson on BART is a tragedy and we continue to extend our deepest condolences to the Wilson family. We are thankful the suspect is in custody due in large part to our surveillance system,” Trost said.

“Nothing is more important than the safety of our riders and employees … . Our hearts break for the Wilson family. Their grief must be unbearable. BART as an agency will continue to do all we can to ensure a safe trip for our riders.”

Wilson’s family has expressed sorrow that she won’t be able to pursue her dream of joining the military and work in the medical field.

“Nia’s dream was to join the military and be an emergency medical technician. As her dad sadly adds, ‘we will never see my baby again. And she will never be able to pursue her dreams. No parent should ever have this experience in their life,’” the law firm said in a statement, according to the newspaper.