Bogotá, February 20 (RHC-EFE) -– Colombian police said Thursday that they arrested a U.S. citizen on charges of aiding the FARC, the Andean nation’s largest guerrilla group.

Nicknamed “El Gringo,” the American supplied communications gear and other electronics to the Revolutionary Armed Forces of Colombia, or FARC, police said in a statement.

While police did not provide the man’s name, media outlets identified him as a missionary named Russell Martin Stendal.

The American’s attorney, Eder Castro, told El Tiempo newspaper that his client approached authorities when he learned that he was under investigation for alleged ties to the FARC.

The missionary arranged to meet with an investigator and was arrested when he showed up for the appointment, Castro said.