The Tachikawa Police Department received reports from residents who heard "two small, cannon-type bangs" around 11 p.m.
Investigators discovered an "improvised launch device" comprised of two metal pipes, lead wire, and a battery in an empty lot near the base. Yokota spokesman Captain Ray Geoffroy reported no injuries or damage. No projectiles have been located, and no one has claimed responsibility.
[Stars and Stripes]