(CNN) -- Three Delaware day care workers were arrested after police got hold of a "disturbing" and "shocking" cell phone video that, authorities say, shows two toddlers taking part in a fight the workers had organized.
Police said Tuesday that they arrested Tiana Harris, 19; Estefania Myers, 21; and Lisa Parker, 47, who have been charged with assault, reckless endangerment, endangering the welfare of a child and conspiracy.
On Saturday, authorities responded to an unrelated incident and a person whom police would not identify showed them video of the 3-year-old boys fighting in March.
The toddlers were not seriously injured, but they were "clearly hurting each other," said Dover Police Capt. Tim Stump.
Authorities have not released the video but say one day care worker said "No pinching, only punching" after one of the boys complained that the other had pinched him.
The video purportedly shows seven other children seated in the room with their backs to the fighting, according to police.
"It's not like they didn't know what was going on, and they were just encouraging them to continue," Stump said. "One of the children attempted to run, but one of the teachers pushes him back into the fray.
"We are looking into the possibility that this was not the first time it happened, but it appears to be isolated, and it seems the administration was in the dark about this," he added.
Police made the arrests Monday and addressed the incident that evening with parents and guardians of the children who attended the day care center.
A spokesman for the state Division of Family Services said the agency dispatched an institutional abuse investigator to work with Dover police during their investigation.
"Depending on our findings, these women could be prohibited from working in the public sector, especially with children or senior citizens," agency spokesman Joseph Smack said, adding that all three women had passed background checks before their employment at the center.
"It's rare to see a case like this where the staff encouraged this type of behavior," Smack said.
Calls to the day care center were not returned, though police say the company's business license has been suspended.
The three suspects and their attorneys could not be immediately reached for comment.
Police said the women have posted $10,000 bail and are awaiting trial.