A HEARTBREAKING video shows children throwing rocks at another child after a teacher told them to do it to “teach him a lesson.”

The worrying incident took place at Teach N Tend Daycare in Forrest City, Arkansas.

A whistleblower at the childcare centre filmed the incident once she realised what was going on.

She quit her job, went to police on April 26 to file a report, and emailed the smartphone footage to the police,Fox 13 reports.

The woman said that she and other employees were outside when she saw the teacher in question tell the four-year-old to go and sit down.

Agitated, the boy allegedly picked up some rocks and threw them at the ground.

According to the police report, the teacher then instructed the students to throw rocks at the boy. A half-dozen or so children then began to pelt the child, while he howled in pain.

An officer who watched the video entered the below statement into a police report:

“I observed approximately six toddlers throwing rocks at a white male toddler. The toddler is kneed [sic] down covering his face crying. A background voice says, ‘He’ll learn to stop, OK that’s enough.’”

The former employee who filed the report says that she has witnessed other such incidents at the childcare.

However, the owner of Teach N Tend, Carla Busby, claims the police report was filed by a disgruntled former employee.

Teach N Tend did not respond to news.com.au’s request for comments, but Ms Busby told Fox 13 that any other comments will come from her lawyer.

Both Child Care Services and Arkansas Police are investigating the incident. The teacher who encouraged the students has been interviewed by police.

raffaella.ciccarelli@news.com.au | @raffaella_cicc