In the Line of Duty

The first US Congressman to be killed in the line of duty was Leo Joseph Ryan, Jr. He was a representative from the 11th district in California.

In 1978, he was asked by family members to investigate the People's Temple, which had relocated from California to Guyana. The People's Temple was a religious cult led by Jim Jones.

Congressman Ryan, his aide, and several others visited the compound on November 17, where at first, they were well received. However, things eventually turned sour, and a first attempt was made on the Congressman's life. It was decided that the group should leave and try to resolve the problems at Jonestown at a later time. Upon leaving, Jim Jones decided that Congressman Ryan should not be allowed to return to the US. He ordered the Congressman killed and Leo Ryan was gunned down in at an airstrip, waiting for his flight.

Sources: Rick A. Ross Institute, Wikipedia, Political Graveyard