Chung Hwan Park had been working at Anna Mountain Prayer Church Retreat Center in Urbana, in the state of Maryland.
Song Su Kim, a thirty-year-old homeless man, has been charged with Mr Park's murder, and the attempted murder of his wife Ae Suk Ko.
According to the Washington Post, Mr Kim, who is a U.S. citizen of Korean descent, told authorities that he had long felt disrespected by fellow Koreans and had hit a breaking point.
Kim is being held without bail. He told investigators that he wanted to "invade a Korean" for the way all Koreans treated him, according to charging documents. He told authorities he had had those thoughts for eight years.
The missionary couple, both pastors from South Korea, were visiting the United States on a pilgrimage and were volunteering as cooks at the retreat, Frederick County Deputy State's Attorney Nanci Hamm said.
Authorities had declined to release the victims' names on Monday as they were working to notify family members through the South Korean Embassy.
