The partial DNA profile that was obtained back in 2002 by Dr. Cydne Holt for the ABC television show "Primetime Thursday" was collected from the outside of the stamp. No genetic material was obtained from behind the stamp, or the seal of the envelope, or anywhere else that would have most certainly belonged to the Zodiac.



What Holt found could have been left by the mailman who held the letter. Or any of a number of others.



Arthur Leigh Allen, Kjell Qvale and every other suspect "cleared" via a comparison to the Holt evidence sample is back in the running. And had "The Hunt for the Zodiac Killer" been successful in using said DNA to compare to Sullivan and Kane, it wouldn't have mattered had the result been negative.



My source is a retired SFPD inspector. His information was confirmed by Holt.