A Scott County school bus driver was arrested this week and charged with assaulting a 5-year-old boy on the bus.
A video of the incident shows Durbin Wallace picking the child up by the upper torso, and in the process, "the child's head struck the window of the bus," said Georgetown police Captain Robert Swanigan.
"You can audibly hear the head strike the window, and you can hear the child call out in pain," Swanigan said.
He said the video then shows Wallace picking the boy up and carrying him a few rows back, where he forcefully "planted him down in the seat."
He said "it's really hard to tell" from the video footage what might have precipitated the incident.
"He wasn't out of his seat," Swanigan said of the child. "He was ... I would call it squirming around in the seat."
Swanigan said the investigation began Wednesday, when the superintendent's office contacted the police department.
Wallace was arrested Thursday on a charge of fourth-degree assault of a child, but he later posted bond and was released.
The Scott County school district posted a statement on its website Friday saying that the boy was a student at Western Elementary School and that the district was "working closely" with the police.
"While we can share few details pending the outcome of the investigation, we thought it important to reaffirm to parents and community members that student safety is a top priority for Scott County Schools," the statement says. "Please know that we have taken steps to ensure students remain safe in our care as we continue to investigate this situation with diligence."