Nataline Sarkisyan died Thursday night at about 6 p.m. at University of California, Los Angeles, Medical Center. She had been in a vegetative state for weeks, said her mother, Hilda.

Mark Geragos, attorney for the girl's family, said he plans to ask the district attorney to press murder or manslaughter charges against Cigna HealthCare in the case. The insurer "maliciously killed her" because it did not want to bear the expense of her transplant and aftercare, Geragos said.

Nataline had been battling leukemia and received a bone marrow transplant from her brother. She developed a complication, however, that caused her liver to fail.

Doctors at UCLA determined she needed a transplant and sent a letter to CIGNA Healthcare on December 11. The Philadelphia-based health insurance company denied payment for the transplant.