(CBS/AP) WOBURN, Mass. - A jury has rejected an insanity defense and convicted a Burlington man of killing his longtime girlfriend in her home, a slaying witnessed by a friend of the woman's teenage daughter who was video chatting with the girl.
Christopher Piantedosi was convicted Monday of first-degree murder for the May 2012 stabbing death of 38-year-old Kristen Pulisciano.
According to CBS Boston, Christopher Piantedosi was found guilty of murder by deliberate premeditation and extreme atrocity. He was sentenced to life in prison without the possibility of parole.
Prosecutors say the 40-year-old Piantedosi stabbed Pulisciano more than 30 times because he was angry she wanted to end their relationship.
Investigators reportedly said the victim's daughter was video chatting with a friend on her Ipad in her bedroom, and when she heard the fight, she went to the living room. The victim ran into her daughter's bedroom and Piantedosi followed her with a knife, according to the station.
The Ipad that was left in the bedroom was reportedly still on and the teen friend that was chatting with the victim's daughter witnessed Piantedosi breaking the door open, pushing Pulisciano on the bed and stabbing her numerous times.
The victim's daughter reportedly tried to get the attacker off her mother but when she was unable to, she fled the house and called police.
Authorites say minutes after the stabbing, Piantedosi texted a friend with what he had done. He then threw away his bloody clothes and changed into clean clothes, which prosecutors say showed he was fully aware of his actions.
The defense said Piantedosi has a history of mental illness and was under the influence of prescription drugs.
Piantedosi is also the man who police had previously nicknamed theafter he admitted to stealing a woman's wallet and GPS in New Hampshire. Police say days after the robbery, he knocked on the 61-year-old woman's door to return $90 and the GPS, along with an apology letter he signed "stupid." He later turned himself in.