There are a number of contributing factors that led to the fall of Raccoon City. Of particular importance is the Mansion Incident that occurred in late July 1998, reported by the Special Tactics & Rescue Service (S.T.A.R.S.). According to the report, the staff and residents of the old mansion located in the Arklay Mountains were all infected by the T-virus, an engineered mutagenic pathogen created as a biological weapon by the Umbrella Corporation. The mansion was destroyed following the S.T.A.R.S. investigation and, unfortunately, all evidence of Umbrella's illegal genetic research was destroyed as well when the facility self-destructed. This meant that the S.T.A.R.S. had no substantial proof of Umbrella's wrongdoing and their attempts to convince the police department were futile as Umbr