A member of a vigilante group known for stopping migrants at the U.S.-Mexico border has been arrested for allegedly impersonating a U.S. Border Patrol agent, court documents show. Last week, Jim Benvie was charged with fraud after The Daily Beast reported he was suspected of running a child-cancer charity scam. Reuters reports Benvie, spokesman for the so-called Guardian Patriots, was arrested on the separate impersonation charges Friday in Oklahoma. The Justice Department alleges that Benvie, 44, passed himself off as a Border Patrol agent in April. Earlier this year, the Guardian Patriots split from another armed border group, the United Constitutional Patriots. Benvie remains in federal custody pending a detention hearing tomorrow in Oklahoma before his full trial gets underway in Las Cruces, New Mexico.