The handwriting analyst stated "The other thing that left an impression on me is this very unique way that their making those dots in between the numbers for the times (the colons). They're very strong, very dark, very what I call dot grinding. I found it on the Albany letter and then also look at this, the time on one of the known writings, exactly the same thing." Below is the original Zodiac letter, my cleaned and enhanced version and the History Channel version.
You will notice the lack of speckling in the respective images, along with other small differences, but in particular how I enhanced the lower dot on the colon. So when they are comparing the bold, dark dot, penned by the hand of a killer, they are actually comparing something created by me, and the last time I checked I hadn't killed anybody.