Washington - The girl was coming out of a room next to a flight of stairs, a daycare worker walking behind her.
As the four-year-old was standing on the edge, her left hand on the handrail, the daycare employee forcefully pushed her down several steps, causing her body to slam against a wall.
Then, 52-year-old Sarah Gable looked up at the surveillance camera that captured what she had done to the child.
"She's just a little thing, and she shoved her like a rag doll," said Superintendent Michael Chitwood of the Upper Darby Township Police Department.
The incident happened on Friday afternoon at a day-care center just outside of Philadelphia. The camera had been installed at Child Care of the Future just a half-hour earlier, Chitwood said.
Another employee, Shawayne Tavares, was watching the feed from the camera and witnessed the incident. She confronted Gable, Tavares told reporters.
"I was so upset. I had tears in my eyes... You don't put your hands on a child," Tavares, a manager at the daycare facility, told NBC10 Philadelphia.
Tavares said Gable told her that the girl's shoe caused her to fall.
"I'm like, 'It's not her shoe. I just watched you on camera do it,'" Tavares told NBC10 Philadelphia.
Police were called shortly after the incident. Gable, who started working at the center less than a year ago, has been fired.
The girl had a minor knee injury, but is otherwise fine and went back to the daycare facility the following day, Chitwood said.
Gable has been charged with simple assault, harassment and danger to the welfare of a child. Chitwood said a reckless endangerment charge was likely to be added. The identity of Gable's attorney was unclear.
The video shows Gable bending over after she pushed the girl, likely helping the child get up. That's when she saw the surveillance camera. She then took the child's hand and the two walked down the rest of the flight of stairs.
"She had no remorse, no explanation for what happened, why she did it," Chitwood said.
Gable, who has no criminal record, has been released after posting bail.
Child Care of the Future is a licensed daycare center in Pennsylvania. Records show the facility's license has no history of sanctions or license suspensions.