Coast Guard Investigative Service The Coast Guard Investigative Service ( CGIS ) is a division of the United States Coast Guard that investigates crimes where the Coast Guard has an interest . It is composed of civilian ( GS - 1811 ) , active duty , reserve enlisted , and warrant officer Special Agents . Mission . The mission of the Coast Guard Investigative Service ( CGIS ) is to conduct professional criminal investigations , engage in law enforcement information and intelligence collection , provide protective services , and establish and maintain law enforcement liaison directed at preserving the integrity of the Coast Guard , protecting the welfare of Coast Guard people , and supporting Coast Guard and Department of Homeland Security ( DHS ) maritime law enforcement and counter - terrorism missions worldwide . Authority . The Coast Guard Investigative Service is a federal law enforcement agency whose law enforcement authority is derived from . This authority provides for Coast Guard special agents to conduct investigations of actual , alleged or suspected criminal activity ; carry firearms ; execute and serve warrants ; and make arrests . The criminal investigative function of the Coast Guard Investigative Service is similar to that of a major crimes unit at a large metropolitan police department , investigating crimes such as those " internal " to the Coast Guard , including fraud , larceny , homicide and rape , as well as " external " investigations of maritime - related crimes ranging from migrant and drug smuggling , false distress calls , and violations of the environmental laws . The Coast Guard Investigative Service is a centralized directorship managed by a professional criminal investigator who reports directly to the Coast Guard ' s Assistant Commandant for Intelligence . It is located outside the Coast Guard ' s operational chain of command . CGIS Special Agents . The CGIS special agent workforce is composed of active duty military , reserve , and civilian personnel . However , virtually all CGIS investigators , criminal , counterintelligence , and force protection personnel are sworn civilian personnel with powers of arrest and warrant service , with the exception of a small number of reserve military personnel . All CGIS Special Agents have full arrest powers under Title 14 section 95 of the United States Code . The active duty military component is composed of Enlisted Personnel and Chief Warrant Officer investigator positions . The civilian component is composed of GS - 1811 - 11 to SES criminal investigator positions . Firearms . The Coast Guard Investigative Service ' s standard issue firearm is the SIG Sauer P229R DAK or SIG Sauer P239 DAK in . 40 S & W . Appearance in popular culture . In March 2010 , the character of Abigail Borin , a fictional CGIS Special Agent portrayed by actress Diane Neal , appeared on the hit television drama " NCIS " in an episode entitled " Jurisdiction " . Special Agent Borin appeared again in January 2011 , in the episode " Ships in the Night " , as CGIS joined the NCIS team in the investigation of the murder of a U . S . Marine Corps officer on a dinner boat cruise on the Potomac River . The story illustrates CGIS ' s law enforcement responsibilities along the United States ' rivers , coastlines , and inland waterways in support of the Coast Guard . She returned for a third time in the episode " Safe Harbor " , which had a plot that illustrated the role of the CGIS in supporting the Department of Homeland Security ( DHS ) through maritime law enforcement and counter - terrorism missions worldwide .