Cydne Holt of the San Francisco Police Department crime lab developed a partial DNA profile in 2002 from saliva on the stamps and envelopes of the Zodiac’s letters — particularly the stamp on the November 8, 1969 card — for the ABC News program Primetime Thursday. The profile was compared against Arthur Leigh Allen and Donald L. Cheney; neither matched, so both were excluded as the DNA contributors. Sources stress that a partial profile cannot point to a single person and can only include someone as a possibility or exclude them.