The body of Maleesa Mooney, 31, was discovered on 12 September inside her home after her family raised the alarm when she had not been seen for a week.
Her death is being treated as a homicide but police have not been able to identify exactly how she died.
Ms Mooney’s family believes she was murdered, according to KABC, but police detectives have been unable to reach a final conclusion.
The model was found to have had cocaine and alcohol in her system at the time of death by the coroner.
There were also no signs of forced entry at Ms Mooney’s apartment, and it is unclear how a killer may have entered her apartment. No arrests have been made in the case.
Ms Mooney’s sister, Jourdine Pauline, said she died following a “struggle” and her death was not quick.
She told NewsNation: “She was in a struggle, both her ankles were broken ... her hands, her legs. It’s very gruesome details. She was definitely in a struggle. It wasn’t something that quickly happened.”
The model was reportedly beaten so badly that the mortician cried and told her family not to look at her body, Ms Pauline added.
“All I know is it was a torturous act,” she said.
The medical examiner said they cannot determine “what role drugs or alcohol may have played in her death, if any.”
But they said the beating she endured was not enough to kill her.
“The blunt force traumatic injuries observed at autopsy are generally not considered acutely life-threatening on their own,’” the medical examiner wrote.
“However, based on the circumstances of how Ms Mooney was found, these injuries suggest she was likely involved in a violent physical altercation prior to her death,” the medical examiner continued.
She was last seen in surveillance footage at her apartment Skye at Bunker Hill on 6 September, six days before she was found dead. Police believe Ms Mooney’s death was an isolated incident.
Ms Pauline described Ms Mooney as the “most amazing girl ever.”
“She’s so kind, she’s so genuine, she’s so loving,” she said. “To have someone do what they did to my sister, to that calibre, is sick. It’s demented.”
Ms Pauline also posted a heartfelt tribute to her sister writing, “This is so sick I can’t believe my baby big sister is gone...the reason I’m me is because of you!!!” She added, “I’m still waiting for a call to tell me this isn’t real.”
Eleanor Davenport described Ms Mooney to The Independent as her “best friend.” She said they would talk on the phone for hours, describing Mooney as her “twin sister” since they are just four months apart in age. Mooney was “one of the smartest people I’ve ever met” but also had a “big heart” and was “always sharing love with people,” Ms Davenport added.