The Glenbrook South High School sophomore was found wounded in her bedroom and later died at Lutheran General Hospital.

In May, Lilly's mother, Christine Maga, publicly expressed frustration that no charges had been filed.

Maga said she had been told by officials with the Cook County Sheriff's Office that investigators had gathered sufficient evidence to support charges against a suspect, but that prosecutors were seeking additional time to review the case.

At the time, Maga argued the circumstances surrounding her daughter's death warranted criminal charges.

 This is someone who came into my home. Was let in. Was in my daughter's bedroom while my other daughter was watching a movie in the other room. And heard a loud bang,  Maga said in an interview with FOX Chicago.  And he came out, and he had the gun and my daughter protected herself with the pillow. And he asked for a hug, and she told him to get out. I'm not sure what that was about. He called his mother on the phone to come pick him up, and he left. 

Maga also said she feared for the safety of her other children because the person she believes is responsible remains in the community.