In his book "Threatening Anthropology" anthropologist David H. Price discusses FBI documents from 1945 in which FBI Director J. Edgar Hoover ordered an FBI investigation of Marvin Opler after the discovery of a letter bearing the initial "M" in a Portland trash can. Marvin Opler was questioned by the FBI. One of many anthropologists investigated, the bureau was seeking to discover whether Opler had any Communist Party affiliation. He responded that the only party he had ever been a member of was the Democratic Party, which he had been involved in up until he moved to Tule Lake. The FBI also discovered that Opler was held in high regard both by his coworkers at Tule Lake, as well as by the interned Japanese Americans. One WRA employee informed the FBI that Marvin Opler was considered a "wobbly," a "conscientious objector," and a "long hair" by people in the WRA. This informant was unable to give any reasons for this point of view, however. The FBI described Opler as being "cooperative and courteous" and ended the investigation.