The Zodiac left two messages via payphone at Springs and Tuolumne, and Main Street.
In the Zodiac (2007) movie during the Melvin Belli clip it stated "Pacific telephone says you must keep him on the line for 15 minutes." That is 15 minutes to trace the call, which was about right with the technology available in 1969.
If Zodiac was a resident of Vallejo or Benicia in July 1969, it is often conjectured that Zodiac maybe traveled back home, stashed the gun and returned back to the payphone to place the call, hence the 40 minute delay from the attack to the placement of the call. This phone call had risks attached to it, only 3.7 miles from the crime scene, especially with police milling around the area. Why didn't the Zodiac make the phone call from the privacy and absolute safety of his own home, a short 20/30 second call carried no risk whatsoever. Was he married and needed privacy, did he own a telephone or did he even live in near proximity. Thoughts................

