A man who stabbed his mother to death Friday evening told authorities that God had told him to do it. Authorities in Pinal County say 65-year-old Ronna Thomas died and her 63-year-old sister was injured after Thomas’ son, 38-year-old Joseph Cecil, attacked both women with a knife.

Pinal County Sheriff spokesman Tim Gaffney said Cecil only stopped his brutal attack when a neighbor intervened, hitting Cecil with a shovel to subdue him. Gaffney said sheriff deputies arrived at the 1800 block of west Camino Grande at about 6 p.m. to find a blood-covered woman in the front yard and Cecil lying on the ground with a man standing over him with a shovel.

Inside the home, deputies found Thomas with multiple stab wounds, said Gaffney. Gaffney said Thomas was taken to Casa Grande Regional Medical Center, where she later died.

Her 63-year-old sister was taken by air ambulance to a Phoenix area hospital, where she is in stable condition, said Gaffney. Sheriff Paul Babeu stated, “Had it not been for the intervention of the neighbor who stopped the attack, we would have undoubtedly had another homicide victim.”

Babeu added, “When homicide detectives asked Joseph Cecil why he stabbed the two victims, he told them, ‘God told me to do it.’” Cecil was booked into the Pinal County Adult Detention Center on charges of first-degree murder, attempted murder and aggravated assault.