'Not suspicious' is the ruling on those three cars that caught fire at Cleveland Youth Detention Centre yesterday.
Investigators have hosed down speculation that the cars were set alight after reviewing the CCTV footage.
Authorities are now looking at the possibility of something inside one of the cars sparking up because of the hot temps.
Investigations will continue as to how the fire in the BMW spread to other vehicles.
Firies say this incident is a big reminder to not leave lighters, or aerosols in our vehicles especially in extreme temperatures.