The ones who fought in the war received amnesty I think. However, many of them ended up behind bars later anyway, since that was the only way of life they knew, the gulags were later full of former criminal who served as soldiers. However, there was a mass amnesty in 1953 when Stalin died, both criminals and political prisoners were freed, and there has been a gigantic increase of criminal activity that year.

Unfortunately, I don't know that much about that period. I only remember that from 1947 to several years later the death penalty was abolished and substituted with a maximum 25 years in prison, then it was re-introduced in the 50s. In the later years of the Soviet Union there was the death penalty or the maximum 15 years in prison. So, in the 90s when the mafia groups were already strong in Russia, when the death penalty was definitevely abolished in 1997, can you imagine what a gift for gangsters who were tried for the crimes committed before that year? Even though theoretically they deserved the death penalty but, since in was abolished and the only other maximum penalty in those times was 15 years. So, even when they were proven to have committed 20-30 murders, they didn't get more than 15 years unless they did something after 1997 when the new laws were introduced. Sometimes the death penalty was replaced with life in prison, but it depended on each individual court and judges' decision. So much chaos during those times.