Jennifer Beck was on the porch of her York City home Wednesday morning when she saw two teenage boys running from a house across the street. They were laughing, she said.

"And I came back out, and that's when I saw the fire," Beck said.

The two-alarm fire displaced nine people, damaged four row homes in the 300 block of Oak Lane and was officially ruled an arson that afternoon, said David Michaels, acting York City fire chief.

"There was no other way the fire could've started," he said.

Beck's account of seeing the kids was also a factor in the arson ruling, Michaels said.

The total estimate of damages is $100,000, he said. No injuries have been reported, he said, and the American Red Cross is providing assistance.

What happened: City police and fire personnel investigated the homes and, based on where the heaviest damage was, eyewitness accounts and video footage, determined that the fire was caused by an exterior source, Michaels said.

There had been a few mattresses between the homes that were to be thrown away, Beck said, and their location matched the area with the most damage.

"It is really terrible," she said. "The kids should be in school."

The boys looked to be about 13 or 15 years old, Beck said. Her mother, Karen Beck, is afraid they will return, she said.

"They might come back to see what they did," she said. "I hope they catch them."

Recovery: Fire crews were able to contain most of the damage to the two middle homes, with only smoke and fire-control damage on the end homes, Michaels said.

"The biggest challenge was how close the homes were," he said.

A look at the harder-hit homes shows structural damage on their sides - so much that one can see through the blackened wooden frames.

"It ain't my house no more," said Linda Turner, whose house was one of the more damaged ones.

She hadn't yet stepped inside but was worried about everything inside that could be ruined, she said. With family, friends, neighbors and pastors from her church beside her, she remained calm.

"They're beautiful people," she said of her entourage.

Turner is a strong person, and the situation is in the Lord's hands, said her sister Gloria Conrad.

"She'll be fine," she said.

York City Police are investigating, and anyone with information may call the department at 717-846-1234.

-Reach Mollie Durkin at mdurkin@yorkdispatch.com.