SAN JOSE (CBS SF) — Fire burned at an elementary school in San Jose Friday morning and authorities were determining whether arson was the cause.

The fire at Cornerstone Elementary School on the 1500 block of Lucretia Ave. burned the administration building before it was brought under control at about 6:46 a.m.

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The San Jose Fire Department said the fire started on the outside of the building and spread to the inside. There were no reports of any injuries.

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A person of interest was detained for questioning in the fire. The fire department said there was a series of small rubbish fires in the area in the hours prior to the school fire..

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The fire at the school was not connected to two other house fires in the city overnight, one on Eastside Drive and McKee Road and another at Park Johnson Place. The fire department said none of the fires were related.