Video footage of an adolescent girl in Southwest China's Chongqing attacking a toddler has shocked the nation.

In a tape released on Chongqing TV on November 27, the toddler, Yuanyuan, is shown being accidentally left behind in an elevator by his grandmother. The 12-year old girl, who has just entered, is alone with him in the elevator.

For no apparent reason, the girl then throws Yuanyuan to the ground and kicks him as the elevator heads to the 25th floor, when, as the door opens, she throws the boy out of the elevator, following after him.

Yuanyuan was found by his grandmother five minutes after the events depicted on the tape on the lawn below the building, the tree branches above him broken. "His eyeballs were bulging, his head swollen, his face was bloody, and he was unconscious," Wu told Chongqing TV.

Yuanyuan suffered a skull fracture and a pulmonary hemorrhage, but regained consciousness on Tuesday. He is still under observation in the ICU at the Children's Hospital of Chongqing Medical University, where doctors are planning surgery.

The girl's father, surnamed Li, told the Beijing News that "Police investigation showed that my daughter beat and kick the toddler on the balcony, but (she did) not deliberately throw the boy down. He might have been frightened by a dog barking and fallen off the balcony himself."

According to Li, his daughter said she attacked the boy because he made an unfriendly grimace at her. "She wanted him to smile at her and be friendly to her."

Li said his daughter loves small animals and kids, "but her ways of expressing herself have problems."

Zong Chunshan, director of Beijing Youth Legal and Psychological Consultation Service Center, told the Global Times that the girl might have been physically abused in the past. Li confirmed to the Global Times that he and his wife used to beat and curse his daughter.

The principal of Taoyuan Primary School told the Beijing News that the teenage girl got along well with her classmates and behaved normally.

Yuanyuan's mother, surnamed Zeng, went to the district people's court Wednesday to file a civil litigation case against the girl's family, the Beijing News reported.

Li said after the attack the girl was  crying and poorly behaved and his wife has taken her to Xinjiang.