A 27-year-old man is accused of setting an early morning fire at his cousin's house that killed five children and left a firefighter and three others injured, police and a relative said Sunday.

The fire may have stemmed from a family dispute, the relative said.

Zachary Q. Meeks of Quincy was arrested Sunday at his home and is facing preliminary charges of first-degree murder, aggravated arson and arson, police said.

Adams County State's Attorney Jon Barnard said he will likely file formal murder and arson charges against Meeks on Monday, the Quincy Herald-Whig reported in a story on its Web site.

Rescuers responded to a house engulfed in flames at about 3 a.m. and later discovered the five bodies inside, authorities said.

"When they arrived, the house was pretty heavily involved in flames," said Keith Frank, an assistant fire chief.

The four boys and one girl were found on the second floor of the house, said Adams County coroner Gary Hamilton.

Hamilton identified the children as Kendall Edwards, 10; Althea Clark, 9; Camron Clark, 5; Khalil Clark, 3, and Kejuan Clark, 5 months, according to the Herald-Whig.

The children's aunt, Michelle Gavin, told WGEM-TV in Quincy that Meeks, who is her cousin, poured gas on the front of her sister's house and set it on fire.

The parents, Jeanette and Keith Clark, were down the street when the fire started, Gavin said. They were both injured while trying to save the children, she said.

"I'm devastated," Gavin said.

She said there was a dispute between the victim's parents and Meeks stemming from a drug-related prison sentence handed down to another family member, the newspaper reported.

And about an hour before the fire, Meeks and Jeanette Clark got into an altercation at a casino about the prison sentence, the newspaper reported, citing Gavin.

"I know people will be making something out of it because she (Jeanette) wasn't home with her kids," Gavin said. "But Jeanette is a good mom. She doesn't drink hardly at all and she loves those kids."

Area residents said the children were well-behaved.

"They were well-dressed and clean, and they always said hello," neighbor Sue Johnson said. "I would see them walking down the street to go to church and they were always very nice. They stayed in the yard and always behaved."

Meeks was being held at the Adams County Jail Sunday. Police released few details about their investigation at a Sunday afternoon news conference.

Hamilton declined to release preliminary causes of death and said autopsies are planned.

The fire seemed to spread quickly and flames could be seen shooting through the house's windows, neighbors said. Firefighters said they could see smoke from at least a quarter-mile away.

Two people taken to nearby Blessing Hospital were treated and released, said hospital spokeswoman Chris Tysinger. A third victim was airlifted to a Springfield hospital in critical condition, said Quincy Police Sgt. Doug Schlueter.

Gavin said Keith Clark was the victim airlifted to Springfield.

A firefighter, who suffered burns to his face, was recovering from minor injuries, Frank said.

State and local fire authorities were investigating the fire.

Quincy, which sits along the Mississippi River, is about 90 miles west of Springfield.