RESEDA — The Los Angeles County Medical Examiner ruled that Reseda High School student Khimberly Zavaleta died of natural causes, listing the cause of death as a spontaneously ruptured cerebellar arteriovenous malformation. Zavaleta was struck in the head with a metal water bottle thrown by a fellow student at the school on Feb. 17 and died on Feb. 25.

Zavaleta was trying to protect her sister during the incident, suffered a brain injury, spent several days in a coma, underwent surgery and died at the hospital. She was first brought to a hospital on Feb. 17 complaining of a headache and was discharged, then rushed back on Feb. 21 in distress, when she was diagnosed with arteriovenous malformation.

"Catastrophic bleeding due to a rupture develops quickly — within seconds to minutes — and is immediately life-threatening. Unfortunately, as in Khimberly's case, spontaneous rupture is a common initial presentation of an AVM." Chief Medical Examiner Dr. Odey Ukpo said. According to the Cleveland Clinic, arteriovenous malformation is a rare congenital tangle of blood vessels with no capillaries between them, and a rupture in the brain can cause a stroke and severe brain damage.

The Los Angeles Police Department launched a homicide investigation after Zavaleta's death, and a juvenile was arrested in April on suspicion of murder. The Los Angeles District Attorney's office is reviewing the case.

Zavaleta's family filed a civil lawsuit against the Los Angeles Unified School District in March alleging negligence, inaction, and failure to protect and properly respond to a child in distress. The lawsuit remains pending.

Attorney Jose Jordan addressed the impact of the ruling on the proceedings. "For the coroner to say that the water bottle was not the reason of her death, then it really does weaken the civil and the criminal case," Jordan said.

Robert Glassman, an attorney representing the family, disputed that the ruling alters the underlying events. "Then she was struck in the head at school with an aluminum water bottle, complained of serious head pain, and within days suffered catastrophic brain bleeding that took her life. No press release by the medical examiner changes those facts," Glassman said. "We will continue fighting for accountability for Khimberly and her family."