SEATTLE (January 28, 2013)--Seattle police are working to track the history of a nonfunctional missile launcher that showed up at a weapons buyback event.

Detective Mark Jamieson said a man who was standing outside the event on Saturday bought the military weapon for $100 from another person who was there.

The single-use launch tube assembly for a Stinger portable surface-to-air missile had already been used.

Jamieson said detectives planned to notify the Army Criminal Investigation Command on Monday.

Jamieson says the launcher is a controlled military item and that's not available to civilians through any surplus or disposal program offered by the government.

He said it's most likely that the launch tube was obtained unlawfully from the military, and would likely be returned to Joint Base Lewis-McChord.