clothesline post. >> in about 20 minutes, i got a signal that was in the proper reading range as far as the detector was concerned for a shell casing. i went down, got a plug, turned it over and sitting in the plug was a .25 caliber shell casing stuck to the bottom. when you look at it, and you see the patina on it, you know, it's not a freshly buried object. >> my first thought was this is too good to be true, this cannot be the one that he actually fired. >> investigators hoped that after 15 years in the ground, the shell could still be tested. it doesn't operate out of basements or back alleys. it grows more sophisticated every day. if it were a business, it would be a fortune 500 company.