In the early morning hours of October 15, 2020, a quiet street in Arivaca, Arizona, became the scene of a tragedy that would claim the life of 55-year-old Monica Gilkey. Around 1 a.m., Pima County Sheriff's deputies were called to the 17000 block of West 3rd Street following reports of a shooting. Upon their arrival, they discovered a grim scene. Another woman, 33-year-old Kaycie Mattias, was found deceased at the scene.
Monica Gilkey, who was Kaycie's mother, was found with life-threatening injuries.
Emergency services rushed Monica to a nearby hospital in an attempt to save her life. Despite their efforts, she succumbed to her injuries and was pronounced dead. The initial investigation painted a picture of a deliberate act of violence, leaving a family and a small community in shock. Witnesses at the scene provided crucial information to the authorities, stating that the person responsible for the shooting had fled immediately after the incident.
Through witness interviews and diligent detective work, authorities were able to identify a suspect in the double homicide: 36-year-old Justin Tyler Grandstaff. A search for Grandstaff was initiated, and with the assistance of the U.S. Border Patrol, he was apprehended at the Arivaca Checkpoint. Following his arrest, Justin Tyler Grandstaff was booked into the Pima County Adult Detention Center. He was charged with two counts of first-degree murder in connection with the deaths of Monica Gilkey and Kaycie Mattias. While an arrest was made, the motive behind the fatal shootings was not immediately made public.
