Last month a guy in upstate New York claimed his best friend confessed to the Zodiac killings, he was (in this telling) Louis Myers who began his killing spree at age 17, inspired to do so because of a breakup with his girlfriend. That's why he targeted couples. Myers (apropos name, huh?) died in 2001.
There is evidence that puts Louis Myers in the right place / right time to have committed the twisted series of murders that took place in the Bay Area of California in 1968-69. Here's more on the story and a closer look at the killings.