Phoenix police said the 11-year-old girl, identified only as Emily, has a catheter in her heart that could get infected and jeopardize her life, ABC News reported Sunday.
Surveillance video shows Emily, who recently fought off an infection and had an arm amputated, walking out of the Phoenix Children's Hospital Wednesday night, ABC News said.
"Her parents are now removing her from the hospital and putting her in danger by not providing that last bit of medical attention that she needs," said Sgt. Steve Martos of the Phoenix Police Department.
The search has been difficult for officers, Martos said, the search has been difficult because Emily and her family are from Mexico and there are no records of them in the state.
Police said Emily's mother, identified only as Norma, removed her daughter's IV before walking her out of the hospital in street clothes. The family left in a black van and have not been seen since.