Thirty-two months after Steven Russo, a Seneca Valley High School math teacher, was gunned down at his home, investigators have identified his suspected murderer.

But state police will never arrest 46-year-old Richard Laszczynski, the presumed killer.

Laszczynski, who apparently spent the better part of his life battling mental demons, blew himself up last month with a homemade bomb at his Hampton Township home, authorities said.

An autopsy ruled the June 27 death a suicide caused by a “blast injury to the head and neck,” according to the Allegheny County Medical Examiner’s office.

“It appears he may have had something to do with his own death, while making bombs at his house,” said one investigator who did not want to be identified.

But the source also seemed to leave open the possibility that Laszczynski’s death by explosive could have been accidental.

“He had a history of problems,” the investigator said, declining to elaborate.

Those problems — psychological, pathological or whatever, say friends — may have contributed to his not-so-petty criminal past, too.

Laszczynski in 1994 was convicted of the armed robbery of a post office in Warrendale. While serving time in federal prison, he would later become a jailhouse informant for prosecutors investigating a triple murder in Virginia.

More recently, he was arrested last fall after attacking his wife and stepson with a hammer and knife, Hampton Township police said.

But before Hampton officers could get there, the highly intoxicated Laszczynski used the same knife to intentionally cut his face, according to court documents.

“He was a suspect in the Russo homicide,” Butler County District Attorney Richard Goldinger said of Laszczynski on Wednesday. “But our investigation is still ongoing.”

While state police suspected Laszczynski almost from the outset of their investigation, they never publicly named him or anyone as a suspect in the slaying.

Russo, 48, was shot in the head Nov. 24, 2010, inside the log cabin-style home in Lancaster Township that he shared with his girlfriend Heidi Smith.

Police during the investigation obtained numerous search warrants. They simultaneously got court orders that kept those warrants sealed, arguing that public disclosure of the material could jeopardize their probe.

But at least some of those court papers were recently unsealed with Laszczynski’s death. Contained within the documents is some of the evidence suggesting why police suspected him of killing Russo.

“I think it’s pretty obvious,” Goldinger said. “He was the former boyfriend of (Russo’s) live-in girlfriend.”

The motive was an age old one.

“We believe it was just jealousy,” said state police Cpl. Daniel Herr. And a lot of rage.

“He had some real anger issues,” Herr said of Laszczynski.