According to police, officers were dispatched to the home of 84-year-old Joyce Dexter after someone called 911 to report a domestic disturbance.
Officers reportedly arrived on the scene to find Zachary Weston, dressed in blood-soaked clothing, standing over his grandmother with a knife.
Police say Weston, who also lived at the residence, stabbed his grandmother at least 111 times. Many of the stab wounds were directed at the woman's heart, according to medical examiners.
Weston also allegedly slit his grandmother's throat, cut open her abdomen and then removed some of the woman's organs.
Weston's family told local media that he was mentally ill, stating that Weston told friends and family that he had been "hearing voices" recently.
Weston also had a growing criminal record according to state records. In 2010 Weston was arrested after he assaulted his mother and then punched two police officers who were attempting to remove him from her home.
In August of this year, Weston allegedly punched two employees at the University of Utah's Neuropsychiatric institute.
In September, Weston reportedly swallowed a rock and poured scalding water down his own throat. he was then admitted as a patient at LDS hospital where he allegedly jumped through a window into a nurse's station and attacked employees who attempted to restrain him.
Weston was arrested again in late September after he allegedly attacked his father and bit a woman who was visiting his father's residence.
Zachary Cole was booked into jail and charged with aggravated murder.
