Politial prisoners, that is individuals who openly opposed the Nazis and common criminals or Greens as they were often called were also killed in the Concentration camps. There was no systematic extermination of these two groups and they were more often killed as a result of overwork or disease. Homosexuals or pinks are estimated to have had between 10 and 15 thousand killed. Another persecuted group were the Jehovah Witnesses and estimates range between 2,500 and 5,000 were executed plus more than 200 Witnesses were tried and executed for refusing military service. The largest non-jewish victims of the Holocaust were Romas or Gypsies of whom no less than 250,000 were exterminated. There were also about 300,000 Soviet prisoners of war killed in the camps.