Complex sentence: Rauff delegated the task of keeping the gas vans operating in the Soviet Union and other Nazi-occupied areas to an SS chemist, August Becker, who kept Rauff fully informed on the gas van killing operations.
Split into simpler sentences: Rauff delegated the task of keeping the gas vans operating in the Soviet Union and other Nazi-occupied areas to an SS chemist, August Becker. Becker kept Rauff fully informed on the gas van killing operations.