By Steve Large

YUBA CITY (CBS13) — Investigators are trying to figure out what caused an explosion that leveled and Yuba City home, with two people inside.

They survived.

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The site of the Yuba City blast is fenced off, and locked up.

The home that once stood there is now unrecognizable, blown to pieces.

Before the explosion, it was a three bedroom, two bath, 1400 square foot home.

The homeowner John Lee was inside when it exploded. He has first and second degree burns all over his body. Incredibly his girlfriend survived with scrapes and and bruises. Now friends are trying to raise money for John Lee’s recovery setting up a “Go fund me” page.

Balbir Bains is one of Lee’s friends and says he was woken up by the blast even though he lives a mile away.

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“It was in the morning, about 6:10,” Bains said. “My House shook like someone ran into it.”

The Yuba City Fire Department released photos of the explosion aftermath.

Friends say the blast came as Lee was just getting out of the shower, and his girlfriend just getting in. The protection from the walls of that shower possibly saving both their lives.

“We gotta know what happened,” Bains said. “That’s really terrible what’s happened so hopefully we can come to a conclusion.”

Investigators are focusing their probe on a PG&E main gas line leak found 75 feet from the home.S o far the investigation has not determined that leak to be the cause. PG&E is replacing a mile of that 40-year-old line.

A utility spokesperson issued a statement reading, “Our thoughts are with the people impacted by this incident. ”

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A home blown to pieces. With people inside, miraculously surviving. Now the search for what went wrong.