Complex sentence: He was a member of extreme right terror organisation Organisation Consul (OC) and one of the assassins, who murdered on 24 June 1922 minister of foreign affairs Walther Rathenau.
Split into simpler sentences: He was a member of extreme right terror organisation Organisation Consul (OC) and one of the assassins, who murdered 24. Juni 1922 minister of foreign affairs Walther Rathenau.