Major Nidal Malik Hasan, an Army psychiatrist, is in custody in the rampage that left 12 dead and 31 injured in Texas. In an act of violence that sent shock waves through the American military establishment and raised questions about base security, a man armed with two handguns allegedly opened fire Thursday afternoon on the grounds of Ft. Hood, the country's largest military base. Twelve people were killed and 31 others injured. The suspect, an Army psychologist, was shot and in custody.