The Spencer Mansion was constructed in the Arklay Mountains in the 1960s by George Trevor, an architect who subsequently disappeared. The mansion housed an underground laboratory used by Umbrella Pharmaceuticals for top-secret bio-weapons development on behalf of the US military. Soon after the ε strain's completion in 1998, the virus broke out and infected the staff, causing noticeable necrosis of the skin, and severe brain damage which limits their intelligence and triggers the excessive production of hormones, making them murderously angry; obsessively hungry, and growing several inches. In their volatile state, they are unable to prevent their mutant test-subjects escaping, leading to a number of deaths of hikers and suburban factories. In July 1998, the Raccoon Police Department, unable to solve the murder and animal attack cases, hands over the investigation to S.T.A.R.S., an elite law-enforcement unit funded by Umbrella.
