The lawyer for her family says almost no one looked into her death because the foster care system is "a system without accountability".
"They don't have a voice, they don't have people who will speak out on their behalf," Darren Kessler, the lawyer for Mariah's brother Jeremyah through his guardian, Shannon Villanueva, told the East Bay Times.
Mariah and her brother Jeremiah were taken from their mother and placed into foster care in September 2015, following allegations of abuse and neglect.
Just days into being placed with the foster family, Mariah began "acting strange", according to the lawsuit.
She was talking to herself, shaking and sweating and had hallucinations, claiming there were monkeys and bunnies running around.
A urine sample revealed meth in her system.
Police and the hospital reported the case to social workers however the girl remained in the same home.
Less than two weeks later, she died.
The lawsuit says she died in the arms of her brother.
She wasn't speaking properly and claimed to be seeing spiders.
Jeremiah reportedly told the foster parent, Maria Refugio Moore, but by the time the paramedics arrived, little Mariah was unresponsive.
"Logic compels interpreting Mariah's senseless death and exposure to methamphetamine, twice in two weeks, as an obvious product of abuse and neglect," the lawsuit says.
Her brother was removed from the home later that day.