Police arrested the 16-year-old twin daughters of Conyers murder victim Jarmecca "Nikki" Whitehead Friday morning and charged them with the murder of their mother. Tasmiyah Whitehead and Jasmiyah Whitehead will be tried as adults, according to Conyers Police Department Chief Gene Wilson, due to the nature of the crime. "This investigation has taken place over a several month period of time," said Wilson, and involved the Conyers Police, Rockdale County Sheriff's Office, and the Rockdale County District Attorney's Office.