Police say the 24-year-old son of a Rhode Island couple found buried in their backyard cesspool killed his parents with a garden hoe. James A. Soares was charged Sunday with the murders of 60-year-old James A. Soares Sr. and 53-year-old Marian Soares. He's being held until his arraignment Monday.Major Steven O'Donnell says police believe Soares killed his parents July 9. They were reported missing six days later. On Saturday, police found the couple's bodies in their backyard. O'Donnell said the hoe was found under the senior Soares' body. Police said the younger Soares was the prime suspect early in the investigation. He was taken into custody Friday. Police would not comment on a motive or say whether Soares confessed.