Mentally ill man, 20, found guilty of killing mother

Damian Cornell McElrath received a life sentence in prison Thursday for stabbing his mother to death in their west Cobb home in July 2012.

McElrath was found guilty but mentally ill on charges of murder, felony murder, and aggravated assault, according to a news release from the Cobb County district attorney's office.

Prosecutors agreed with the defense, that McElrath was mentally ill at the time of the crime, but Deputy Chief Assistant District Attorney Jesse Evans said even if McElrath's mental state was altered, there was no justification for the stabbing.

"Justification means self defense," Evans said in the release. "He is guilty but mentally ill. Being mentally ill never excuses criminal conduct."

The attack happened July 16, 2012 and at the time, McElrath told police his mother was "trying to kill him and had been poisoning him for years," according to the release. That day McElrath stabbed his mother in the neck and torso more than 50 times, according to the medical examiner. After the assault he called police and changed his clothes. He was sitting outside the house, smoking a cigarette when police arrived.