During World War II, Fort Missoula was turned over to the Department of Justice, Immigration and Naturalization Service, for use as an alien detention camp holding foreign nationals and resident aliens, unlike the War Relocation Authority camps that held Japanese Americans. Between 1941 and 1944, the fort held 1,200 non-military Italian men, 1,000 Japanese resident aliens, and a handful of German resident aliens. The Italian men included merchant seamen, New York World's Fair employees, and the crew of the Italian luxury liner Conte Biancamano, seized in the Panama Canal. Many of the Italians, who called the fort Bella Vista, spent the war as paid laborers replacing American men working in forestry, farms, the sugar beet industry, and on U.S. Highway 12 contracts. After the bombing of Pearl Harbor on December 7, 1941, the FBI arrested many prominent Japanese leaders on the West Coast as potential security risks, and more than 1,000 Japanese men, all resident aliens barred by law from U.S. citizenship, were held at Fort Missoula for loyalty hearings. No one was ever charged with any act of disloyalty, but all were held there or at other camps for the duration of the war. These enemy alien hearings were conducted in a courtroom in the Post Headquarters building T-1. Fort Missoula remains one of the most intact World War II internment sites, with most major buildings from that era still in use, including the Post Headquarters and its courtroom, the hospital, connivery, officer and staff housing, barracks, and other support structures.