Complex sentence: Mark is placed in juvenile lock-up (partly to protect him, partly to make him talk) but manages to escape, and he and Reggie go to New Orleans to confirm that the body is located where Romey said it was.
Split into simpler sentences: Mark is placed in juvenile lock-up (partly for protection, partly to make him talk) but he escapes. He and Reggie go to New Orleans to confirm that the body is where Romey claimed it was.