On the morning of April 19, 1995, Timothy McVeigh, a former U.S. Army infantryman and Persian Gulf War veteran, parked a yellow Ryder rental truck in the daycare drop-off zone beside the Alfred P. Murrah Federal Building in Oklahoma City. Inside the truck was a massive improvised bomb made with around 2,200 kilograms (4,800 pounds) of ammonium nitrate mixed with nitromethane , a potent homemade explosive. McVeigh lit the fuse, locked the truck and then hurried to his getaway vehicle. Minutes later a devastating explosion enveloped the Murrah building. The blast killed 168 people, including 19 children who happened to be in the building's daycare center. At the time, the bombing was the largest single terrorist attack suffered by the United States. The attack was a wake-up call for the U.S. government and an incentive to review threat assessment and practices at the federal, state and local law enforcement levels.