Complex sentence: During World War II, Pratt was interned into a prison camp where he bought comics from guards: in 1944 he had risked to be executed as SS troops had mistaken him for South African spy.
Split into simpler sentences: During World War II, Pratt was interned into a prison camp where he bought comics from guards. In 1944 he was at risk of being executed as SS troops had mistaken him for a South African spy.