
One rarely covered communication is the "Ambler Tours" letter postmarked Los Angeles County and credited with two dates of March 7th 1986 and March 12th 1986 Mailed to "(Redacted) Ambler Tours 101 2ND AVE. Suite 1900 SAN DieGo, CA. 92101", it has very little information attached to it in the FBI files, other than the sender appeared to be addressing the San Diego owners and founders of Ambler Tours & Travel Agency, Frank and Virginia "Ginny" Ambler. They had two sons, Dale and Wayne. The ZIP code 92101 corresponds to the city of San Diego, California, and is primarily associated with downtown San Diego, including areas like the Gaslamp District and Petco Park. Something about this letter, so distant in time and location to the main body of Zodiac communications must have peaked the interest of law enforcement to have found its way into the Zodiac FBI files.
This letter arrived about two months before the "Freeway" letter on May 6th 1986, and approximately 10 weeks after the release of Robert Graysmith's book "Zodiac". Letters postmarked Los Angeles were not unprecedented in the Zodiac case, with the previous two California letters from the Zodiac Killer having both been mailed from this location on May 2nd 1978 and July 19th 1978. The "Channel 9" letter sent to KHJ-TV at 5515 Melrose Avenue in Los Angeles on May 2nd 1978, was postmarked in Anaheim, a city in Orange County and part of the Greater Los Angeles area..Therefore, we have three known letters postmarked in this locality within an 8 year period (absent to the knowledge of others).
The only crime that has regularly been touted as a potential Zodiac attack was the double murder of Johnny Ray Swindle (20) and Joyce Ann Swindle (19) at Ocean Beach in San Diego on February 5th 1964,.when they were murdered on a concrete patio overlooking the sea by a sniper situated approximately 50 feet away. Perched on the bluff above the patio, the sniper fired five shots at the couple from this distance, before walking down to where Johnny and Joyce lay and firing two more shots from near point blank range into their heads. Their location on the patio just beneath the terminus of Narragansett Avenue can be found only 5.5 miles northwest of the Ambler Tours & Travel Agency office.

The previous year, on May 7th 1985 a comprehensive newspaper article on Johnny and Joyce Swindle featured in the San Diego Union newspaper, in which ongoing work was still being undertaken on the case. A recent television news story on the Swindle murders had generated "one pretty damn interesting phone call", which Sergeant Ed Stevens forwarded to the current homicide lieutenant, Paul Ybarrondo. Sgt Stevens is still of the belief that the murders were committed by a teenage boy "thrill sniper", despite no evidence forthcoming on the age of the unknown murderer in 1964.
The 1986 "Amber Tours" letter would have been an unusual deviation for the Zodiac Killer, directed toward a business. However, it would be followed two years later, on February 1st 1988 and February 8th 1988, by two letters aimed at the McDonald's regional office at 2 Northgate Park in Chattanooga, Tennessee, with the signature "This is the Zodiac" introduction. Seemingly, two threats on businesses, both withheld from the newspapers. Without further information on this correspondence it is practically impossible to determine if the author of the "Ambler Tours" letter was the infamous Zodiac Killer, but it certainly doesn't hurt to explore the possibility. I may do a FOIA request for this letter in the near future.