http://en.wikipedia.org/wiki/Leo_Ryan

Leo Joseph Ryan, Jr. (May 5, 1925 – November 18, 1978) was an American politician of the Democratic Party. He served as a U.S. Representative from California's 11th congressional district from 1973 until he was assassinated in Guyana by members of the Peoples Temple shortly before the Jonestown Massacre in 1978. http://en.wikipedia.org/wiki/Jonestown

After the Watts Riots of 1965, then-Assemblyman Ryan took a job as a substitute school teacher to investigate and document conditions in the area. In 1970, he investigated the conditions of California prisons by being held, under a pseudonym, as an inmate in Folsom Prison, while presiding as chairman of the Assembly committee that oversaw prison reform. During his time in Congress, Ryan traveled to Newfoundland to investigate the practice of seal hunting.

Ryan was also famous for vocal criticism of the lack of Congressional oversight of the Central Intelligence Agency (CIA), and authored the Hughes-Ryan Amendment, passed in 1974. He was also an early critic of L. Ron Hubbard and his Scientology movement and of the Unification Church of Sun Myung Moon. On November 3, 1977, Ryan read into the United States Congressional Record a testimony by John Gordon Clark about the health hazards connected with destructive cults. Ryan is the only U.S. Member of Congress killed in the line of duty. He was awarded the Congressional Gold Medal posthumously in 1983.