Complex sentence: Lee was arrested that morning based on these notes and his apparent familiarity with the body, in that his initial statements were that the girl was white when the police, because of the filth and darkness in the basement, had thought she was black.
Split into simpler sentences: Lee was arrested that morning based on these notes and his apparent familiarity with the body. His initial statements were that the girl was white when the police, because of the filth and darkness in the basement, originally thought she was black.