HOLLY SPRINGS, N.C. — A child was left alone on a school bus right before a fire broke out on the vehicle here on Tuesday morning, school district officials said.

A spokesperson from Wake County Public School System who was not identified by CBS17 told the news source that the bus driver had started the bus, pulled it to the bus loop in front of Holly Springs High School, and went inside the school to drop off a paper. However, when the driver came back outside, smoke could be seen coming from the vehicle, and that the driver and school staff had to evacuate the child off of the bus. (The child was not a student at the school but was in the care of the bus driver. According to the spokesperson, the district's bus drivers are allowed to have non-students in their care on their buses.)

Lisa Luten, a district spokesperson, told WRAL.com that the bus involved in the fire was taken out of service last February to have its engine replaced, and then put back into service in November, according to a preliminary investigation. Officials added that the fire may have been caused by a “worn spot on a wire” that was located near the bus’s newly replaced engine. Currently, all of Wake County Public School System's buses undergo monthly inspections, Luten told the news source. She also said that the district's bus drivers are not supposed to leave running buses unattended.

On Thursday, Luten said in a written statement, obtained by WRAL.com, that out of the district’s 870 buses, 48 are of the same make and model similar to the bus that caught fire. Of those buses, Luten said 20 were inspected on Tuesday following the fire, installing protective coverings on the wires leading to each of the buses' alternators, and that the remaining buses would be inspected and updated on Saturday. Luten also said, according to WRAL.com, that the district is working with a different third-party vendor to conduct an additional review regarding the cause of the fire.

As School Bus Fleetpreviously reported, another Wake County Public School System bus caught fire in October while a bus driver and an elementary student were on board. School district records reportedly showed that the bus had undergone a maintenance inspection earlier that day.