WILKES-BARRE (AP) — A man accused of killing three children by setting fire to their northeastern Pennsylvania home faces a life term following conviction on second- and third-degree murder and arson charges.

Jurors deliberated for about four hours Tuesday before convicting Preston Bonnett of Wilkes-Barre in the October 2017 fire in Laflin that killed 7-year-old Ezekiel Major, 12-year-old Devon Major and 16-year-old Erik Dupree.

Luzerne County prosecutors said Bonnett, 28, is the ex-boyfriend of the children’s mother and briefly stayed at the family’s home until he was thrown out. They argued that the evidence was clear that he used a lighter to set fire to curtains inside a window he had smashed with a beer bottle a few weeks earlier.

First Assistant District Attorney Sam Sanguedolce also cited testimony from a witness that Bonnett had previously threatened to burn down the mother’s house, and — reminded of the presence of the youngsters — said she “deserves to see those children burned,” Sanguedolce said.

“That is evidence of specific intent to kill,” he said.

Bonnett repeatedly asserted his innocence, and defense attorney Bernard Brown presented witnesses who said the cause of the fire couldn’t be conclusively proven. He acknowledged that his client had been present at the time of the fire but said police were only able to “guess” that he used a lighter to start the blaze.

“What you have, ladies and gentlemen, was simply that Mr. Bonnett was on the back porch at that time,” Brown said. “There isn’t enough evidence to convict him.”

Bonnett, who faces an automatic sentence of life in prison without possibility of parole on the second-degree murder conviction, swore at prosecutors after the verdict was announced.