Complex sentence: The abandoned camp was liberated on January 19,1945, by the Polish resistance soldiers from the local unit of "Armia Krajowa"; some 350 prisoners remained alive when the Red Army arrived a week later.
Split into simpler sentences: The abandoned camp was liberated on January 19,1945, by the fighters from the local unit of "Armia Krajowa" Polish resistance organization. Some 350 prisoners remained alive when the Red Army arrived a week later.