U.S. Marshal

A U.S. Marshall is an officer of the United States Law Enforcement Agency within the Department of Justice. They are the highest-ranking ranking law enforcement officers in the country, and belong to the oldest such agency in the country.

Marshalls are responsible for protecting court officers, witnesses, and federal and state buildings.

Criminal Minds
Agent Sam Kessmeyer is given the task of protecting Haley Brooks and her and Hotch's son, Jack. Federal Marshalls have also appeared as minor characters in other episodes.