ELKHART, Ind. -- A man who stabbed two women in a northern Indiana city is a person of interest in a nearby house fire that killed a father and two sons, and a man who burned to death inside a car registered to the same person committed suicide, authorities said.

Police have released few details since the blaze early Monday morning at an Elkhart home that killed 38-year-old Jose Aguilar and his sons, 13-year-old Ricardo and 7-year-old Adolfo. But they have said all along that the fire, the stabbings and the subsequent death of the man in the car following a police chase are related.

On Wednesday, Elkhart police identified Francisco Macias, 31, of nearby Goshen as the person who stabbed the two women just hours after the fire. Both women survived the attacks. Police also called him a person of interest in the arson attack, but said there was "insufficient evidence to state that he is the perpetrator of this incident."

They have not yet identified the man who died in the car registered to Macias because of the severity of his burns.

Police said in a statement Wednesday that they would not comment further until the investigation is complete. Elkhart is some 150 miles north of Indianapolis.

Elkhart Assistant Fire Chief Shaun Edgerton said the fire started about 1:50 a.m. Monday when someone threw a jerry-rigged propane tank through the dining room window.

"He opened the tank, he used some sort of wicking mechanism and then set the wick on fire and hurled the tank through the window. The propane then spilling out becomes an incendiary device. It's kind of like a blow torch," Edgerton said.

The fire gutted the house and melted some of the siding on a neighbor's house.

Coroner John White said Wednesday that the man in the car died of burns and ruled his death a suicide. He would not say what led him to that conclusion, saying police had asked him not to comment. White said an autopsy was inconclusive in identifying the body and that DNA testing is necessary.

White said the two Aguilar boys died of carbon monoxide poisoning and that the father probably did too, but that more testing was needed