LINCOLN, Neb. (AP) — Lincoln fire investigators say they believe natural gas caused an explosion that leveled a home and injured two people.

Fire investigators are seeking an internal cause for the explosion that destroyed the home Monday afternoon and damaged others nearby in southeast Lincoln.

A Black Hills Energy spokeswoman says Tuesday the utility has determined the explosion wasn’t due to the natural gas delivery system to the house’s gas meter.

The owners of the home, whose names haven’t been released, remained at a Lincoln hospital in critical condition.

The explosion shattered windows and knocked some neighboring homes off their foundations. Debris from the shattered home was scattered for blocks.

Neighbor Diana McCoy says she thought a plane hit her house: “The concussion of it was just incredible.”