St. Louis prosecutors filed a felony child endangerment charge against Steven Herrmann, 48, of Poplar Bluff, the television station reported.
According to court documents, the girl's mother reported the child missing after Hermann had not returned from St. Louis. Hermann was watching his granddaughter for four days beginning Aug. 19 and was visiting a family member in a hospital, KTVI reported.
When Herrmann did not return with the girl, police began a search. He was found in an alley in the southern section of St. Louis, and when a family member arrived, Herrmann allegedly locked the child in a car and fled, the television station reported.
Police retrieved the child from the car and took her to a hospital, where doctors found cocaine in her system, KTVI reported.