From an aircraft's exhaust and they are very accurate, anywhere below 11,000 feet. >> with this mystery at hand, how are they going to figure out the source? >> reporter: the seattle police are working with the military at joint louis mccord, the airbase in tacoma. right now, they are trying to look at the serial numbers because every weapon has a serial number and a lock number so the weapons can be traced. and the weapons can give them an expiitration date so they canro rotate the older ones on of service. we are told they are easily accessible in libya and afghanistan. military experts say ...