A fire killed six people, including four children, in a single-family home early Wednesday, officials said, and authorities arrested an 18-year-old man in the blaze hours later.

Michael Davis, of Youngstown, was arrested on six charges of aggravated murder and six counts of aggravated arson, city police said.

The victims included children, ages 2 to 8, and two women, Fire Chief John O'Neill said. As many as five other people were in the house when the fire started.

O'Neill said the bodies of the children and two adult females were found throughout the single-family home on the city's east side. Their identities were not released.

"The house was so burned. you could see right through to the back," said April Martin, who said she worked with one of the women killed in the fire. "You could tell it started on the front porch."

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The fire chief said the blaze started near the front of the house, either on the porch or just inside the front door. It spread quickly and consumed the home.

Police Detective Sgt. Patrick Kelly told The Youngstown Vindicator that it looked as if some kind of accelerant had been used to start the fire on the front porch.

At the house next-door, neighbor Brenda Brown gestured to a hobby horse on its side in her front yard and said it belonged to the neighbor children. She was used to seeing them playing on it.

"They were beautiful little kids, and it's really sad," she told WKBN radio.

Brown said firefighters could not get in the home when they first arrived.

"They couldn't even get in," she said. "They put on their oxygen, they tried to get in, they come right back out. ... So, they just kind of let it burn a minute. They didn't really have very much choice."

By midmorning, homicide detectives were on the scene, and an arson team with dogs focused on the area around the front porch.

"It's in a bad area," Martin said of the home. "It wasn't dirty, but there was a lot of stuff there."

As many as five other people were in the home when the fire started just before 5:30 a.m, O'Neill said.

Three people were being treated at St. Elizabeth Health Center, hospital spokeswoman Tina Creighton said. She said she could not release their identities.

O'Neill said the coroner's office is investigating the relationship among those inside the home. A message seeking comment was left with the office.