James "Jim" Browner was a sailor and the estranged husband of Mary Browner.
When they were first married, the couple lived happily together in Liverpool. However, that happiness came to an end when the couple invited Mary's older sister Sarah to live with them. Sarah fell in love with Jim, and when he rejected her advances, she resolved to destroy their marriage out of spite. She began to turn Mary against her husband, and the couple's relationship quickly deteriorated, even after Jim forced Sarah to leave. Jim, a recovering alcoholic, began drinking again, which further estranged him from Mary. Eventually Sarah introduced Mary to Alec Fairbairn, a young sailor with whom Mary began an affair.
When Jim discovered the affair, he stalked the pair to New Brighton, where he murdered them in a fit of jealously while they were out boating. He then tied their bodies to their dinghy and sank it, knowing they would be assumed to have become lost and drifted off to sea. He also cut an ear off each corpse. He intended to send them to Sarah, who had moved in with her older sister Susan after leaving Liverpool, because he considered her to be the cause of the tragedy. However, Sarah had since moved to another place, and the box, which was only addressed to 'S. Cushing', ended with Susan, who was disturbed by it and thought it was an evil joke. Susan called in the police to investigate the package, and Inspector Lestrade invited Sherlock Holmes to consult on the case.
Holmes eventually discovers that Browner was the source of the ears by matching the box's Irish postmark to the schedule of Browner's ship, and after being arrested Browner revealed the whole sordid tale. As a result, Browner was sent to prison.
Watson indicates that the case disturbed Holmes, who ends the case by asking "what object is served by this circle of misery and violence and fear? It must tend to some end, or else our universe is ruled by chance, which is unthinkable."