Andrew Caldwell was one of the victims of The Chesapeake Ripper.
In Sorbet, he appears in a flashback drawing blood from the arm of Hannibal Lecter then releasing it into a vial for later testing for insurance purposes. Andrew asks the doctor if he's aware of any other infections in his body at the moment and encourages Lecter to tell the truth, since he'll find out anyway and lying just increases his insurance payments. Hannibal asks for the man's business card.
Months later, in the present, Andrew drives along a desolate road he runs out of gas, and he's forced to pull over. As he checks the tank, he sees someone has gouged a hole in it. A car pulls up the road behind him and Hannibal gets out and offers assistance. In the days following, Caldwell's severed body shows up in an empty school bus, his upper body seated next to his lower body, while Hannibal meticulously files clean-cut red meat into his refrigerator.
When his body is examined it is determined that the killer had taken his heart and liver.