Conduct the "harpoon throwing experiment" | The Fate of Black Peter SH: Crimes and Punishments Guide
Last update: 11 May 2016
Talk to Watson and head to Woodman's Lee. Take a Harpoon from the hut. Using the map, reach the Whitechapel Butcher. Talk to Watson and after the conversation, focus on throwing the Harpoon at the carcass.
Hold your breath and aim at the red X. Press the right key (options at the top) when the marker is in the middle of the line. The harpoon has to go clean through the carcass.
Deduction
Connect "Strength requirement" with "Pinned to the Wall". You will obtain two options that rule out one another: "Feat of strength" and "Lucky throw".