Martin Eugen Ekström was a Swedish military adventurer who became the leader of the National Socialist Bloc, an umbrella organization for various fascist and National Socialist groups. Ekström was born in By, Avesta Municipality. During the Finnish Civil War, he led the Vasa Regiment which was responsible for the Viipuri massacre. Lieutenant colonel Ekström led the 3rd Battlegroup of the Swedish Volunteer Corps in the Finnish Winter War. He died in Helsinki, aged 67.

The Viipuri massacre was the killing of approximately 360 to 420 Russians in the city of Viipuri during the Finnish Civil War in April–May 1918. The massacre took place during and after the Battle of Viipuri as the White Guards captured the city from the Red Guards. At least half of the victims were Russian soldiers and military personnel. The slain were mainly men and young boys: nine out of ten were men fit for military service. The White Guards were "cleansing" the city of Red Guards, however, only a small minority of the killed Russians were affiliated with the Finnish labour movement.