Police said they have made two arrests four months after a mother was found stabbed to death at her home in Conyers. Authorities announced Friday that they have charged the victim’s twin daughters, Jasmiyah and Tasmiyah Whitehead, and said that the 16-year-olds will be tried as adults. Both are being held at the Rockdale County Jail. Jarmecca Whitehead, 34, was stabbed to death in January on Appaloosa Way in the Bridle Ridge Walk subdivision in Conyers, police said.