On their visit to Columbus, Aaron and Kathryn Foster toasted marshmallows, chased fireflies, and when it was time to return to Minnesota, pleaded to stay another day. An extension granted, the siblings spent that last day at Magic Mountain, where they posed in a photo booth. Their aunt held the strip of black-and-white photos as she stood Tuesday across the street from her destroyed North Linden home, where her 10-year-old nephew and 12-year-old niece died in a fire that broke out at dawn.

The visit with their aunt had been just a few days long, but brother and sister made the most of it.

Aaron and Kathryn Foster toasted marshmallows, chased fireflies, visited their grandmother in Worthington, and when it was time to return to Minnesota, pleaded to stay another day. An extension granted, the siblings spent that last day, Monday, at Magic Mountain.

"I let them ride the go-karts like a bazillion times," aunt Anastasia Amatulli said. Her sister's children also clowned for the camera in a photo booth, eyes and mouths wide open as they prepared to demolish two lollipops.

Amatulli held the strip of black-and-white photos as she stood Tuesday afternoon across the street from her destroyed North Linden home, where her 10-year-old nephew and 12-year-old niece died in a fire that broke out at dawn.

Investigators said the children were trapped inside the house in the 3500 block of Walmar Drive, just south of Cooke and east of Karl roads. Kathryn was found in the hall and Aaron just a foot or two from the front door that neighbors couldn't break down.

Amatulli escaped the burning house through a back window. Her 23-year-old son, Ryan, also escaped without serious injuries, but attempts by them, neighbors and police to rescue the children were unsuccessful.

"We tried to beat the door down with a sledgehammer," neighbor Joanie Dienno said. "They stopped screaming, and then we knew it was too late.

"I will never ever stop hearing those screams until the day I die."

The fire likely started in the basement, where Anastasia Amatulli said her son stayed and where a space heater and other electrical items had been plugged in. Investigators had not pinned down an exact cause, but police said the fire appeared accidental.

Columbus police Sgt. David Sicilian, supervisor of the first-shift homicide squad, said detectives were working with fire investigators, which is standard procedure when fatalities are involved.

Dienno said a commotion next door startled her and boyfriend Anthony Mazzola awake about 6 a.m.

Mazzola dashed outside barefoot, in only a pair of shorts, while Dienno called 911.

Sicilian said neighbors and the first officers to arrive made "a valiant effort" to save the children, but the heat and flames were already too intense.

Dienno said Aaron and Kathryn were "great kids, beautiful kids, well-mannered kids." They indulged in the old standbys of a central Ohio summer, she said.

"We gave them our marshmallow sticks," she said.

"They were supposed to go home yesterday," Dienno said. "They wanted to spend one more night with their aunt Tasi. She was great with them."

"They were wonderful children," Amatulli said. She lost two dogs in the fire and told neighbors the home was uninsured.

The fire is the third double-fatality blaze to occur this year in Columbus.

A Jan. 8 fire that killed two adults in a Franklinton duplex was started by minors playing with fireworks, investigators said.

Three days later, two young brothers perished when they became trapped in their burning basement apartment on West Town Street, also in Franklinton. Fire officials said that blaze was unintentionally started by one of the boys playing with a lighter.

tdecker@dispatch.com

@Theodore_Decker