SYRACUSE - Prosecutors will let a 27-year-old upstate New York man who killed his parents use an insanity defense as part of a plea bargain.

In a bizarre statement he read aloud in court, Joseph Bisesi said he thought his parents were criminal impostors and that he was an undercover operative acting under CIA orders when he shot them in July.

On Monday, Bisesi pleaded not responsible by reason of mental disease or defect to the charges he murdered his parents, JoEllen and Joseph, and disposed of their bodies in the septic tank at their home in Elbridge, 20 miles west of Syracuse.

A relative found the father's torso stuck in the tank's standpipe - his arms and legs cut off in an effort to fit the body in the hole.

Bisesi was facing first- and second-degree murder charges that could have sent him to state prison for life. Now, he could spend the rest of his life in a state psychiatric facility as a result of the plea.

“There will be a lot of people who listen to this young man's words today and find them funny ... But, it's not funny,” said Onondaga County District Attorney William Fitzpatrick.

Chief Assistant District Attorney Christine Garvey and defense lawyer Randi Bianco both agreed evidence from two psychiatrists showed Bisesi did not understand the consequences of what he was doing at the time of the crime.

Bianco said medical tests showed Bisesi suffers from delusions and schizophrenia. Records show Bisesi was the victim of an assault in April of 2005 and his mental condition has deteriorated ever since, she said.

“You have to keep in mind that this illness to a large extent was caused by the assault on him, the beating about his head. He received such a severe blow that immediately afterward within two weeks he started becoming paranoid,” Bianco said.