The lawsuit alleges that Charlie Bell, who was a CPD officer at the time, gave Hendrix drugs which led to her death. Bell resigned from the department a week after the incident.
Cynthia Hendrix said her heart has been shattered by the loss of her daughter.
"My first born. The one that made me a mother. I don't get sleep at night. I don't eat no more. My child is gone," she said.
In the newly filed lawsuit, the family claims Bell "offered Ms. Hendrix illegal drugs on August 18th and/or August 19th of 2021."
"He had a relationship with a young lady, took advantage of that relationship, and we believe on information and the family believes he supplied drugs for her on that evening or somehow facilitated drugs, and did not protect her when he had the opportunity to protect her when she was staying in his home," said attorney Gregory Kulis.
The Cook County Medical Examiner ruled Hendrix's death an accidental overdose, and found ethanol, cocaine, fentanyl and methamphetamine in her system.
According to the police report, Bell claims he spent time with her earlier that day and that she came back to his RV that night drunk and high.
Her family said while Hendrix did like to drink, she didn't use hard drugs.
"We're going to ask for texts, whatever we can find to determine what really happened that night," Kulis said.
According to the police report, Bell told officers on scene that he found Hendrix unconscious the next morning. He told police he tried to resuscitate her, but she was unresponsive. But the lawsuit alleges Bell "failed to determine if Ms. Hendrix needed medical aid," and "failed to contact, notify, or otherwise alert emergency personnel that Ms. Hendrix was severely intoxicated or impaired."
"And unceremoniously Officer Bell resigned from the department and that chapter suddenly closes and the life of Treasure Hendrix suddenly closes," Kulis added.
The Chicago Police Department said Bell resigned from the department on August 26, a week after Hendrix died. In a statement, CPD said a death investigation remains ongoing, and that "there is an open investigation into the allegations made by the victim's family."
"I'm a mother, and if you have children and something like this occurred, you would want to answer, too," said Cynthia Hendrix.
The lawsuit also cites the Drug Dealer Liability Act, which is an Illinois Law that provides civil remedies to someone injured as a result of illegal drug use.
ABC7 reached out to Charlie Bell, but has not heard back.