Complex sentence: Marv, hearing from Lucille that Goldie was a prostitute, heads off to Old Town for more information before being ambushed by Goldie's twin sister Wendy, who also believed that Marv killed her sister.
Split into simpler sentences: Marv, hearing from Lucille that Goldie was a prostitute, heads off to Old Town for more information. But he is interrupted by an ambush from Goldie's twin sister, Wendy, who believes that Marv killed her sister.