At first glance, breaking news of a business explosion on Sunday looked like an accident.

Now, the state fire marshal said it's a case of arson.

The Nebraska Fire Marshal said on Wednesday that the investigation revealed two things about the fire. One was that someone tampered with the natural gas system in the dry cleaner, which led to the explosion and fire.

The second thing the investigation revealed is that the utility company, Metropolitan Utilities District, has nothing to do with it.

The news of the cause of the explosion rattled nearby business owners for a second time.

"Arson isn't a good thing. With businesses so close and gas stations and so forth, it's hard for me to understand the situation actually," Kevin Irish of the Paw Spa said.

Investigators found evidence of tampering with the gas lines in the building, but there have been no arrests and no suspects named.

Neighbors said the owner was on site behind a van at the time of the explosion.

"I found the owner and thankfully he was outside trimming the bushes at the time," Brianna Rogers said. She works nearby.

The explosion at 168th and Harrison had some neighbors wondering if what happened in the Boston suburbs last month was a possible explanation. In that case, excessive pressure in natural gas lines owned by Columbia Gas caused a series of explosions in dozens of homes.

That wasn't the issue in Omaha.

M.U.D. told 6 News that their "gas distribution system worked as it was designed and there were no failures on the District's gas distribution system. The District stands ready to assist the investigation as necessary."

Hearing the dry cleaner explosion is a case of arson is a bit of relief to neighbors knowing the odds of a repeat event are slim.

"I would say we're a couple hundred yards. We're catty-corner from the place. We found this burnt shoe in our parking lot shortly after the explosion," Irish said.

6 News learned Douglas County deputies responded to the owner of the dry cleaner's home in Valley, Nebraska earlier this week after he reported a break-in and vandalism to his storage unit.

Deputies reported he was distraught.

It is unclear if there is any connection between the Sunday business fire and Monday storage unit break-in.