Original sentence: Although the Russian authorities admitted the crime did happen, there is a growing resentment in Russia over the issue and it is often believed that it was the Germans to kill the Poles after invading the Soviet Union in mid-1941.In the course of the massacre approximately 22,000 Polish citizens were executed in three mass murder sites in the spring of 1940.The Katyń massacre, also known as the Katyn Forest Massacre, was a mass execution of Polish citizens during World War II, perpetrated by the Soviets
Edited sentence: In the course of the massacre approximately 22,000 Polish citizens were executed in three mass murder sites in the spring of 1940, according to the view that the Soviets were responsible; another view is that the Germans killed the Poles after invading the Soviet Union in mid-1941.The Katyń Incident, known in Poland as the Katyn Forest Massacre, was a disputed occurrence resulting in the mass execution of Polish citizens during World War II, believed by some to have been perpetrated by the Soviets