Complex sentence: Rachel is rescued by physician and fellow member of the resistance Hans Akkermans (Thom Hoffman), who had in fact not only been a traitor, but also responsible for the brutal death of her family at the hands of the Nazis.
Split into simpler sentences: Rachel is rescued by physician and fellow member of the resistance Hans Akkermans (Thom Hoffman). But it then emerges that Akkermans had been a traitor and responsible for the brutal death of her family at the hands of the Nazis.