About half of the 2,500 NCIS employees are civilian special agents. They are trained to carry out a wide variety of assignments at locations around the world. NCIS special agents are armed federal law enforcement investigators. They frequently coordinate with other U.S. government agencies. NCIS special agents are supported by other employees. These include analysts and experts in forensics, surveillance, surveillance countermeasures, computer investigations, physical security, and polygraph examinations. At times NCIS will use outside agencies. For example, they have used the Smithsonian Institution to help identify skeletal remains.