Who is Abby Turnbull from All That Remains and what is their importance?

Abby Turnbull is a reporter who once worked in Richmond. A year or two before the disappearance of Deborah Harvey and Fred Cheney, Abby's sister, Henna, was murdered by a serial killer in Richmond. Scarpetta was the coroner on the case and became good friends with Abby during the investigation. Abby has since moved to Washington in order to work for the Washington Post.