Shortly after 3:00 a.m. on June 25, 2024, a forced entry and gunfire at an apartment on Newcastle Drive in Sun City left two women dead. Marcia McGrath, 53, and her 77-year-old mother, Thea Merlino, were found with gunshot wounds. Deputies arriving on a 3:07 a.m. call heard cries for help, forced entry, and discovered Thea dead at the scene; Marcia was critically wounded and later died at a hospital.

Before she died, Marcia identified her attacker to deputies as her ex-husband, Robert McGrath, and gave his residence and a description of his truck. Neighbors reported being threatened that morning by a man later identified as Robert, who had forced them to the ground and taken a cellphone. Marcia had reported prior threats from Robert to the El Mirage Police Department weeks earlier, and a domestic split was recent — she filed for divorce on June 17.

The investigation led to the arrest of 60-year-old Robert Alan McGrath at his El Mirage home. The case centers on motive and the timeline between the June 17 filing and the fatal attack; anyone with information about the days before June 25 or who saw a described truck in the area is asked to come forward.