Who is Pete Marino from All That Remains and what is their importance?

Pete Marino is a detective in the Richmond Police Department. When Harvey's Jeep is discovered at a rest stop, he contacts Scarpetta to look the car over and check for any forensic evidence that would help them identify the killer. Marino also suspects that the FBI and CIA are withholding information and conveys this to Scarpetta. Pete is described as volatile, moody, and prone to drinking.