Prosecutors say a man accused of killing his grandmother in her Avenues home stabbed her 111 times.

Disturbing new court documents were released Friday as Zachary Cole Weston, 21, was charged with aggravated murder, a capital offense.

Weston is accused of stabbing Joyce Dexter, 84, multiple times on Oct. 3. Police were called to Dexter's house, 310 J St., where Weston was living, on a report of a possible domestic disturbance. When they arrived, they found Weston standing over his grandmother while holding a bloody knife, the charges state. He also had blood on his hands and clothing.

Weston told investigators that he "stabbed his grandma" and admitted that he "slit her belly, her jugular and her heart," charging documents state. A medical examiner later determined that nine of the 111 stab wounds were to the heart. Prosecutors said several of the victim's internal organs had also been removed.

Salt Lake County District Attorney Sim Gill could not comment Friday on a possible motive or Weston's possible state of mind at the time of the attack. He praised police, however, for responding so quickly to the crime scene and confronting the grandson before he left.

Family members have told reporters Weston suffered from a mental illness.

Weston has been involved in a recent series of incidents against relatives and others, showing an apparent trend of increasing violence, according to court records.

Last week, he was charged in 3rd District Court in an unrelated assault against another family member. On Sept. 27, Weston, who was living at the time with his father, got into an argument with his dad and began hitting him, according to court documents. When a female friend of Walt Weston, who was also at the house, tried to intervene, Zach Weston allegedly bit her.

In 2010, Weston was arrested for shoving his mother and hitting a police officer. He pleaded guilty to one of two assault charges. As part of his sentence, he was ordered to undergo a mental health evaluation and complete any recommended treatment.

On Aug. 8, Weston was at the University Neuropsychiatric Institute at University Hospital for an initial assessment when he slapped a hospital employee with an open hand, according to a University of Utah police report, and punched another in the face.

For those incidents, he was charged on Aug. 9 with two counts of assault and interfering with a police officer during an arrest, class B misdemeanors. On Sept. 24 he was charged with two counts of battery and making a false alarm, also class B misdemeanors.