CHARLOTTE, N.C. – After a Charlotte-Mecklenburg Schools bus burst into flames last month, the state sent in an expert to try to help determine why.

It appeared the fire started in the engine compartment of the bus that was carrying more than a dozen students from South Mecklenburg High. The students and the driver all got off safely.

The state inspector identified what was called, “an area of interest in the engine compartment," but did not determine a cause.

As CMS continues to inspect similar buses in the fleet NBC Charlotte asked what that area of interest was.

CMS responded Friday, saying it was the wiring in the area of the starter, but as for whether that was the cause of the fire, CMS said, “…it is inconclusive.”

With no known cause and the likelihood now that a cause will never be known, some parents are worried.

Asked if she has confidence in CMS buses, Joan Roberts who has nephews that ride the buses said, “No, I don’t. That was dangerous and pretty serious and I do not have confidence in them.”

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Lynsey Berry said she thought some parents would now start driving their kids to school so they would not have to ride a questionable bus.

“I wouldn’t want to put my kid on a school bus that I thought was going to catch fire," Berry said.