Sources close to the investigation tell the Niagara Falls Reporter they now believe the conflagration that consumed three Seventh Street residences and left seven families homeless was caused by a workman accidentally cutting into a gas line with a power saw.
Sparks resulting from the saw cutting through the metal pipe ignited the compressed natural gas and resulted in the explosion, sources say.
The workman, who has not been identified, is presumed dead, although his body has yet to be found. He has not been seen by family or friends since the Friday afternoon explosion at 440 Seventh Street, and investigators spent the weekend sifting through the rubble in search of his remains. Two dogs, owned by an elderly woman, also died in the tragedy.
"The explosion blew me against the side of the porch after a big boom," a neighbor said. "I know it was a huge gas explosion or something."
Agents from the federal Bureau of Alcohol, Tobacco and Firearms examined the scene to see whether the explosion was caused by a bomb, but rampant rumors of an accidental explosion in an underground methamphetamine lab proved to be incorrect.
Still, representatives from the U.S. Attorney's office in Buffalo were in Niagara Falls as late as Sunday night, leaving no stone unturned in regard to the cause of the explosion and fire.
Falls Police Supt. Bryan DalPorto, who arrived at the scene at the height of the blaze, said the mostly vacant west side of the 400 block of Seventh Street looked like "Berlin after World War II."
Well into Friday evening, a Niagara Falls Fire Department ladder truck kept pouring water on hot spots, mainly on the middle house at 440 Seventh. The other homes are 438 and 442 Seventh.
Niagara Falls Fire Chief Tom Colangelo said every on-duty firefighter in the city responded to the blaze and nearby volunteer fire companies were called in to stand-by at Falls fire stations. Off-duty firefighters were also brought in to assist.
The three residences will be demolished this week, once federal agents complete their investigation.