A jury convicted a Carnegie man yesterday of fatally stabbing his roommate and beheading, dismembering and eviscerating him before concealing the body in a shallow grave.

James Monroe Baldwin Jr., 24, showed no emotion when the panel of seven men and five women returned guilty verdicts for first-degree murder and abuse of a corpse. The jurors had been asked to consider an insanity defense.

Defense lawyer John Elash presented expert psychiatric testimony at trial that Mr. Baldwin, who had no adult criminal record, was suffering from a schizophrenic disorder when he attacked Brendon Glen-David Martin, 19, on Jan. 25, 2006.

"The facts of the case are pretty insane," said Mr. Elash.

The University of Pittsburgh junior confessed to county police detectives that he had a fight with his roommate of five months because he believed Mr. Martin's marijuana use had caused Mr. Baldwin's girlfriend to have a miscarriage.

Mr. Baldwin told police he stabbed Mr. Martin multiple times as Mr. Martin lay on the floor coughing up blood and asking "Why?"

After the verdict, Mr. Elash said he was disappointed that the jury disregarded the testimony of Dr. Laszlo Petras, who evaluated the defendant at Mayview State Hospital for 14 months, and instead appeared to rely on the testimony of the prosecution's expert, who spent an hour and a half to evaluate Mr. Baldwin and determined he'd been depressed but not insane.

The victim's parents said the family has been torn apart by the murder.

Mr. Martin's father, Craig Martin, said he has attempted suicide five times since Brendon died, and had been assigned a service dog to monitor his mood swings. His mother, Sarah Memel, has suffered a heart attack and other health problems that she said were related to the trauma. Ms. Memel, of Lubeck, W.Va., said she felt some relief at the verdict but said Mr. Baldwin "showed no remorse" and the brutality of the crime was difficult to bear.

The CCAC student studied computer science, loved skateboarding and animal husbandry and was planning to transfer to Pitt at the time of his death.

The defendant initially denied knowing the whereabouts of Mr. Martin after detectives questioned him about five garbage bags containing body parts, cutting tools and a shovel. Police learned about the evidence from a Collier road maintenance worker who discovered suspicious bicycle tracks in the snow and footprints that led to the shallow grave about 50 yards off Ridge Road in an isolated, wooded area. Mr. Martin's remains were positively identified from a tattoo.

Sentencing is scheduled before Common Pleas Judge Kathleen A. Durkin on May 14. Mr. Baldwin faces a mandatory sentence of life in prison without parole.