U.S. authorities on Thursday arrested a former U.S. Marine who is a member of a group that allegedly raided the North Korean Embassy in Madrid in February and stole electronics, according to two sources familiar with the arrest.

Christopher Ahn was arrested and had been expected to be arraigned Friday in federal court in Los Angles, according to a law enforcement official and a source close to the group.

Separately, federal agents raided the apartment of Adrian Hong, the leader of the group, The Washington Post reported, citing people familiar with the incident, who spoke on the condition of anonymity to discuss a sensitive law enforcement issue.