Raccoon City police chief Brian Irons had been bribed by Umbrella to hide evidence of the company's experiments in the outskirts of the city. He concealed their development of the new G-virus, an agent capable of mutating a human into the ultimate bioweapon. Leon has multiple encounters with a Tyrant, a monster air-dropped into the Raccoon Police Department by Umbrella to seek the G-virus. Irons tries to murder Claire but is killed by a G-virus mutant in the police department. Claire and Sherry escape through the sewers and become separated. After splitting up with Leon, Ada finds Sherry and picks up a golden pendant the girl loses while running away. Further into the sewers, Ada reluctantly teams up with Leon again, after he insists on his duty to protect her. They encounter a middle-aged woman who fires at Ada, but Leon jumps between them and takes a bullet himself. Ada ignores the unconscious Leon and follows the woman, who reveals herself to be Sherry's mother Annette and the wife of William Birkin, the Umbrella scientist who created the G-virus. In an attempt to protect his life's work from special agents sent by the Umbrella headquarters, he injected himself with the virus, which turned him into the malformed creature and is now chasing Sherry because of her genetic make-up. Annette recognizes her daughter's pendant and attempts to take it from Ada. A fight ensues, during which Annette is thrown over a railing. Ada learns that the golden locket contains a sample of the G-virus, and later – taken over by her emotions – returns to Leon, tending to his bullet wound.