premise: × Possible pipe bomb explosion reported at East Chicago post office EAST CHICAGO, Ind. – Authorities in northwest Indiana are at the scene of an explosion involving possible pipe bombs, WGN reports. The scene is at a post office in East Chicago near Kennedy and Chicago Ave. Reports suggest that a possible postal worker has been injured. We will update this story as more information develops.
hypothesis: Police are already at the scene of the possible pipe bombing in East Chicago.
reason: The article explicitly stated authorities are on the scene. The authority in this situation would be police.