The children's mother escaped the early morning blaze Friday along with the man she is dating, but the children were trapped inside. When police arrived, the two adults were outside fighting with the woman's ex-boyfriend, Francisco David, authorities said.
David, 34, resisted police and was arrested and arraigned Friday on a charge of disorderly conduct. He was jailed Saturday, and District Justice Cheryl Hartman said he didn't yet have an attorney who could comment.
``We're looking at him to be possibly involved in the fire,'' Lancaster city police Sgt. William Gleason said.
Police executed a search warrant Friday seeking evidence that he recently had handled flammable materials.
David had been released from prison two weeks ago and had been trying to reconcile with the children's mother, Cheryl Birster, authorities said.
The victims ranged in age from 4 to 10. A pathologist said the children died of smoke inhalation and ruled the deaths homicides. The fire gutted their two-story brick home.
Birster, 34, and Kevin Haythe, 30, whom she had been dating for several weeks, told police they were inside the home when they smelled something burning.
They told police they jumped from a second-story window to escape heavy smoke and ran to the front of the house but couldn't get back inside. That's where they said they encountered David, police said.
Police initially said they used pepper spray to subdue all three adults, but Gleason said later that only David resisted officers' attempts to break up the fight and that the pepper spray was aimed at him.
Birster is divorced from the children's father, according to court records.