No one was inside the residence on Lambeth Lane at the time of the 2 p.m. blast, said Joliet Deputy Fire Chief Ray Randich.
The house was demolished and the home to north sustained damage.
"It was a defensive attack the entire time," said Randich, telling how the house was fully engulfed in flame when firefighters arrived.
The Lambeth Lane house is off Gougar Road and close to New Lenox.
Randich said investigators were still at the scene of the explosion and trying to determine its cause late Monday afternoon.
"It's up to them to piece this together," Randich said.
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