Nia Wilson's family is suing California's Bay Area Rapid Transit (BART) system, citing the lack of safety precautions as part of the reason for the teen's killing.

On July 22, 2018, Wilson was fatally stabbed, and her oldest sister was injured following a knife attack by a reported "violent felon" while exiting an Oakland train, as Blavity reported. John Lee Cowell, the 28-year-old man accused of killing the young woman, was reportedly a repeat fare evader.

As of December, Cowell was charged with murder by the Alameda County District Attorney and currently faces the death penalty or life in prison, according to KTVU.

The suit, which was filed on Friday, claims that BART officials knew of a connection between fare evasion and crime and did not take necessary precautions which may have prevented the tragedy.

Over the past year, BART has reportedly increased on-site security by hiring civilian fare enforcement officers, surrounding paying stalls with protection walls and locking easy access gates that most turnstile jumpers use to bypass fees.

The San Francisco Chronicle reports the family is not satisfied with recent improvements and are seeking a monetary payout as well as the implementation of new policies to counter issues they claim led to Wilson's death.

The plaintiffs include Nia's parents, Ansar El Muhammad and Alicia Grayson, as well as her sisters, Letifah and Tashiya Wilson. Letifah was stabbed in the neck by Cowell but survived.

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The family is suing the agency for liability, negligence and a heightened risk of injury due to the dangerous condition of the property.

The lawsuit states Wilson would not have died had "BART taken adequate measures to prevent fare evaders from entering BART’s stations, platforms or trains."

"Plaintiffs contend that Nia Wilson’s death was not a horrific anomaly," the complaint reads, "but rather the result of a serious and endemic public safety problem."

HuffPost reports the unspecified grief award would accompany the “Nia Wilson Crime Statistics Notice,” a policy that would require the dissemination of crime rates in select locations to make ticketed riders aware of the area's safety metrics over the previous four years.

BART spokesman James K. Allison responded to the complaint, stating the agency "continues to express our deepest condolences to the friends and family of Nia Wilson," but refused to say more, adding that they "cannot comment on potential or pending litigation.”

“This lawsuit is part of Nia Wilson’s family’s commitment to hold BART accountable for cleaning up its system,” wrote attorneys Robert Arns and Jonathan Davis in a statement on behalf of Nia's family. “No one else should have to suffer because of BART’s failure to protect its riders.”

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