Sherlock Holmes investigates the gruesome murder by harpoon of a very unpleasant former sea captain known as Black Peter. Interest Level: 3-6 Reading Level: 4.2 ATOS Book Level: 4.5 AR Interest Level: MG AR Points: 1 AR Quiz: 147533EN Reading Counts Level: 4.8 Reading Counts Points: 4 Lexile Measure: 660.