(KCEN) -- The Killeen Fire Department has now confirmed there is enough evidence to suspect arson in the Gateway Middle School fire.
Samples from the fire are being analyzed.
Arson is likely because the fire grew so rapidly and burn patterns were discovered on the ground.
The fire department is also looking through surveillance footage.
Neighbors say they saw a suspect running away from the school.
J. D. Gardner of the Killeen Fire Department said, "We did employ the use of a K9 yesterday who found hydrocarbon or accelerant."
Classes resumed today but in a different location.
Leslie Gilmore of the Killeen Independent School District said, "We have moved over to our new facility, our new Gateway Middle School and everything went beautifully this morning."
If you have any information about Saturday's fire you can contact the fire marshals' office or crime stoppers.