Propane Leak Possible Cause of Home Explosion.

July 25, 2012 Updated Jul 25, 2012 at 7:40 PM EDT

By Ed Reilly

July 25, 2012 Updated Jul 25, 2012 at 7:40 PM EDT

TOWN OF WILSON, N.Y. (WKBW) Dozens of community volunteers came to the site of a fatal house explosion to help the family search for personal belongings.

Meticulously sifting through the rubble, residents and church members helped collect photographs, clothing, and mementos that belonged to the family of seven.

Tuesday morning around 6:08am, a 2-story house at 4972 Chestnut Road in the Town of Wilson exploded killing 14-year old Sarah Johnson, and throwing four other family members from the house.

Parents Jody and Judith Johnson, along with two of their children, are at the Erie County Medical Center.

Friends tell Eyewitness news that Jody, a retired US Army veteran, suffered broken ribs and is listed in fair condition.

16-year old Nathan Johnson is also listed in fair condition.

But Judith Johnson, and her soon to be 19-year old daughter, Katie, have more serious injuries.

Katie Johnson is listed in critical condition with severe burns, while her mother, Judith, has broken ribs and fractured vertebrae.

The cause of the explosion is under investigation, but neighbors say the Johnson family smelled something strange the day before the fatal blast and they called NOCO for advice.

"And they told him sometimes when your tank is low like that, you'll smell it in your house. They went around...opened all the windows. And he {Jody Johnson} went around and checked for leaks inside the house with soap and water . . . and couldn't find anything inside," says neighbor Brenda Stunkel.

Niagara County Undersheriff, Michael Filicetti added, "It is an angle that we have to look at. We don't know what action was taken with that odor in the residence. So, they are going to look at that and see if that was a potential cause of the explosion."

16-year old Hannah Johnson and her 10-year old brother, Sam, were not home at the time of the explosion.