If you’re looking to knock out some back-to-school shopping, this week may be the best time to hit the outlets. “I wish tax-free week happened more than once a year. It would be great,” says Jennifer Hudak, who was shopping for her 7-year-old daughter Monday afternoon.

ANNAPOLIS, Md. (AP) — The National Transportation Safety Board, which has jurisdiction over pipelines, is investigating a natural gas explosion at a home in Bel Air, Maryland, that killed two people, the agency said Monday.

Meanwhile, state officials have identified the two people who died, and the state fire marshal’s office said they are focusing on accidental causes because there is no evidence of criminal activity.

Ray Corkran Jr., the 73-year-old homeowner, died in the Sunday morning explosion, officials said. Jose Rodriguez-Alvarado, a 35-year-old contracted utility employee with Baltimore Gas and Electric, also died, the state fire marshal’s office said.

Jennifer Gabris, an NTSB spokesperson, confirmed that NTSB pipeline investigators were on the scene Monday in Bel Air, a town about about 30 miles (48 kilometers) northeast of Baltimore.

Deputy state fire marshals and agents with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives have concluded their on-scene investigation and turned the scene over to insurance representatives, the fire marshal’s office said.

“Crews have already begun cleaning up the copious debris strewn throughout the neighborhood, and restoration companies are beginning to make repairs to nearby homes,” the fire marshal’s office said in a news release Monday.

Investigators will now focus on reviewing the evidence and data they collected on Sunday, the fire marshal’s office said. That includes gas and electrical piping, interviews, video surveillance and data from BGE.

“While the explosion remains under investigation, there is no evidence of criminal activity, and they will continue to focus on accidental causes,” the fire marshal’s office said.

Firefighters were called to the area around 6:40 a.m. Sunday for a report of a gas leak and an outdoor odor of gas. As firefighters were approaching, they began receiving calls that the house had exploded.

Two utility workers were in the area to work on a reported electrical issue at the time.

A woman in a house next door was treated for injuries on the scene.

Neighbors in the vicinity reported a variety of damage to their homes from the explosion. Twelve families were displaced.

“Our hearts are broken for the two victims and their families. Our team of highly qualified investigators and our partners at ATF are dedicated to providing an answer that will lead to safer communities,” said Acting State Fire Marshal Jason M. Mowbray. “A tragedy of this size is heart-wrenching for Maryland.”

More than 60 first responders came to the scene from multiple agencies.