JUST IN: The family of 12-year-old Khimberly Zavaleta Chuquipa, who died after allegedly being bullied at school, has launched a lawsuit against the L.A. Unified School District in California. Khimberly sadly passed away after she stood up to students who were bullying her sister. The family says Zavaleta was hit by a “water bottle and then later suffered a brain injury,” according to ABC 7. "At dismissal time, she was in the school hallway when a tall boy came up to her ... he was pushing her, and my daughter told him, 'What's your problem with me? Let's go to the principal's office and talk about it' -but he ignored her," said Khimberly’s mother. “My daughter goes and pulls her away, so they don't hit her sister, and that's when [Khimberly] gets hit in the head.” “They were hitting her sister-my eldest daughter," Chuquipa said. "In the video, you can see them pulling [Khimberly]. At one point, they hit her hard on the head, which led her to where she is now - in a morgue.” Attorney Robert Glassman says the school district failed to act on previous reports of bullying. He says the bullies were also responsible for bullying other students. "When bullying and violence escalate at a school, that’s a serious breakdown of student safety, and that’s exactly what happened here within the L.A. Unified School District," he said.