Dozens gathered on a bridge above a riverbed where the 18-year-old's body was found March 28.
Her mother, Natalie Mireles, says a coroner investigator initially told her they believed the death was a suicide, but officials now say the cause of death has been deferred pending further investigation.
The Los Angeles County Sheriff's Department says deputies are actively investigating the case, but the family says they aren't getting any answers.
On March 28, Aisha went to the movies with her mother and two younger sisters. Natalie said Aisha was very happy. Later that afternoon, she walked to a friend's house a few blocks away in the city of Hawaiian Gardens.
She didn't go out much and uncharacteristically, did not return by 8 p.m. curfew. Her body was found the next morning about 13 miles away.
Natalie said it's strange and illogical to think Aisha would get there walking alone, adding she wasn't familiar with the area. Natalie has tried, unsuccessfully, to find surveillance footage and has posted flyers asking for help.
Family and friends say there is no way the Cerritos College student would take her own life, and say they have found evidence that leads them to believe she was killed. Days after Aisha's death, Natalie went to the riverbed and found what she believes is her daughter's tooth, as well as her eyeglass lens and backpack, which had a tear in it she doesn't believe was there before.
"I hope that this protest does a difference because she deserves better than this," said Jacqueline Aguilar, Nava's friend. "I know she didn't kill herself. I know someone did it to her. I just hope that she didn't suffer."
Nava's family has posted flyers asking for the public's help and hope Saturday's vigil will encourage anyone with information to speak out. Her mother is demanding a full investigation into the case.