>> to prove their suspicions, police turned to forensic science. first seda was fingerprinted. his prints were then compared with the print left on the letter in central park. it was a match. next, handwriting experts compared the handwriting from the zodiac's letters to seda's known handwriting sample. the experts concluded they were written by the same hand. ballistics experts examined seda's collection of 15 zip guns. in his letters, zodiac claimed no one would catch him because his gun barrel didn't have the traditional lands and grooves inside for testing. but the zodiac apparently didn't know about forensic tool mark analysis. >> a tool mark is a characteristic left behind during the process of using a