Updated 09/10/13 – 11:20 a.m.

LOWELL, Ind. (CBS) — A house explosion Monday night leveled a home in northwest Indiana, and killed a man who was inside at the time.

CBS 2’s Susanna Song reports debris and the home’s foundation were all that remained after the blast destroyed a home in the 7100 block of East 181st Avenue in Lowell, about 25 miles south of Gary. Indiana State Police said flames and smoke could be seen for miles after the explosion around 7:15 p.m.

Lowell Fire Chief Clint Gorball said it appeared a leak in a large propane tank led to the blast.

The body of 43-year-old Victor Strain was found in the basement, hours after the explosion. He lived next door and apparently had gone inside the house after he thought he smelled gas or smoke. The house that exploded was vacant because the owner is in a nursing home.

“He had went to check on the house. He had thought he smelled smoke, saw some burning in the back area of the home, and then as he entered the home, evidently there was an explosion. He was killed instantly,” said Lake County Sheriff John Buncich.

Wayne Wietbrock, a friend of the homeowner, said, “The neighbor was just doing a good deed; come over, check on the house. He flipped a switch, or something, and … gone.”

Wietbrock also had checked on that house before as a favor for the homeowner.

“He’s been in a nursing home, with Alzheimer’s, for the last few months; quite a few months,” he said. “People would just check on the house, make sure it’s alright. Nobody’s lived in the house … since last winter, probably.”

Last Thursday, some other friends were at the house.

“You are a good neighbor to people, and you try to help them out, but you expose yourself when you do this,” Wietbrock said.

More than 100 firefighters from 12 fire departments rushed to the scene after the explosion, and arrived to find debris scattered in an area bigger than a football field. The explosion left chunks of wood and shards of glass everywhere.

“There’s debris probably 100 yards even behind where we’re standing now, so it had to be quite an explosion,” said Lake County Sheriff’s Cmdr. Matt Eaton.

A neighboring house caught fire because of the blast, but no one in that home was injured.

“The first house is completely leveled. The second house has been burnt beyond repair,” Eaton said.

Investigators said there’s no reason to believe the explosion was the result of arson, or anything criminal in nature, but it could take a while to confirm the exact cause of the blast.

“I think that beyond just the cleanup, the [Indiana] State Fire Marshal’s investigation is going to take hours, if not days,” Eaton said.

According to news reports, two firefighters were hurt while putting out the flames.

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