NORTH KINGSTOWN, R.I. (WPRI) — North Kingstown police say an investigation determined there was no criminal conduct after a 4-year-old boy was left on a bus for 50 to 55 minutes.

Police were called to a municipal office building on Fairway Drive after a child who appeared to be lost was found by an employee.

Officers then contacted the boy's mother who came to pick him up.

Police say the boy is enrolled in the North Kingstown School Department's extended school year program and got on the bus with other students that morning.

The driver and monitors unintentionally left the child inside after returning to the bus yard on Fairway Drive. The child eventually exited the bus by himself.

Superintendent Kenneth Duva says the employees have been placed on unpaid administrative leave.

Families expressed concern about the incident, especially given that temperatures reached into the 90s that day.

"We hear about hot car deaths, and it really doesn't take that long before something serious happens," North Kingstown parent Mary McSpedon said.

The temperature inside a vehicle can rise rapidly on hot days.

"There's a lot of body surface area with a child, and so they can heat up very quickly," Jason Rhodes from the Rhode Island Department of Health explained.

 "Always look in the back seat whenever you get out of that vehicle to make sure you are not forgetting something or forgetting someone," he continued.