Although the stranger seems to be blackmailing Roger, his goal appears to be clearing Gaffer’s name for Charley and Lizzie’s sakes, suggesting that the stranger is ultimately acting for good reasons. The stranger’s comment about “sharing” some of the reward for John’s murder is deliberately intended to have multiple meanings. While Roger interprets this as getting a share of the money, it’s clear the stranger means that Roger will “share” in something else—perhaps even blame for committing the murder.