Who is Officer Roscoe from Killing Floor and what is their importance?

The first officer to treat Reacher with any kindness or respect, Roscoe is an attractive woman with large eyes, soft dark hair and a face that radiates intelligence. She is calm and methodical, and an honest member of the Margrave police department. About thirty years old, she is dark but not tall, and has an obvious vitality. Reacher is drawn to her immediately.