The father of a three-year-old pre-K student is in custody after a gun was found in the child's backpack Tuesday morning. A teacher found the handgun and confiscated it before the child entered a classroom. The child, who was unaware the gun was in the backpack, has since been placed in the custody of Child Protective Services. Police arrested the child's 35-year-old father on a charge of child endangerment. The city's pre-K system is temporarily banning backpacks while reevaluating its safety protocols.