In the United States, a special agent is a detective or investigator who investigates suspected violations of federal, state or local laws.[1] Special agents may also carry firearms and make arrests.[1] Special agents work for many different law enforcement agencies. In some agencies, only special agents may carry firearms. An example is special agents in the Internal Revenue Service.[2] To become special agents most applicants must pass written and physical examinations. In the FBI, like many agencies, applicants must go through a background check.