The Zodiac Killer

Only 100 and forty three nine millimeter firearms similar to those used in the zodiac attacks had been sold in san francisco over the last three years. A 22 caliber weapon had been used on david and betty lo while two different nine millimeter weapons were used during the attacks on michael and darlin and paul stein. The one used to kill paul was a semi automatic that required ammunition only available from specialized gun dealers. Investigators hunted down the buyers gun applications and compared their handwriting to that on the zodiac letters. No matches were found.