This was on page 15 of 41 on Zodiac 2 PDF and dated November 6th 1969. The follow up, on page 16 of 41 was regarding the testing of latent fingerprints for comparison to known fingerprints held on file, dated November 7th 1969, in regard to the 11/6/69 teletype. It was important to see what follow up was conducted regarding this sighting. The FBI file below, indicates that the presumed sighting of Xenophon Anthony by the 8-year-old witness was followed up immediately and found that Xenophon L Anthony's fingerprints bore no correlation to the fingerprints on file. Here are the files I managed to acquire from an FOIA request to the FBI.
http://www.zodiacciphers.com/uploads/4/9/7/1/4971630/zodiac2.pdf