Authorities are trying to determine whether a natural gas leak caused an explosion that leveled a restaurant and a shop in Pueblo Thursday.

A gas leak was found in the street next to the restaurant but it wasn't clear whether the pipe was ruptured by the explosion or contributed to it. However, the break was at the joint of a main gas line and a feeder line to another restaurant.

At least one witness said she smelled gas after the blast, but fire department spokesman Woody Percival said it's possible she smelled that gas leak or another one caused by the powerful explosion.

It was about 20 feet from the feeder line to the building that exploded.

Ashley Johnson, 22, was killed in the blast and several others injured.

Eugene Roney, 74, remains at Parkview Medical Center where he is listed in critical condition. Roney was pulled from the rubble after being trapped for more than four hours.

Co-owner of the restaurant, Frank Vigil, also remains at Parkview in fair condition.

Jennifer Flower was flown to Denver Health Medical Center, where she is listed in good condition Friday.

Three other victims were treated and released. One person remains at St. Mary Corwin Medical Center. Their names have not been released.

Local, state and federal investigators, including members of the U.S. Bureau of Alcohol, Tobacco and Firearms, are meeting Friday to determine how to proceed with the investigation.

Percival says the ATF is involved because agents have experience investigating large explosions, not because foul play is suspected.

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