Well thanks to Pink Panther's earlier posts, I took another hard look at Dixie's case, and I found an incredible coincidence. Dixie was born in India, January 1st 1948, her parents being missionaries to that continent; Cecelia Shepard [Zodiac victim of the Berryessa attack] was born in India 1st day of January, 1947, her parents also missionaries. And Schaefer = well, it's a pen, of course, but it's German for Shepherd.
Dixie disappeared August 25 1968,
Zodiac started killing in the Bay Area December 23 1968,
Blue Rock Springs, July 4 '69,
Berryessa was 27 September 1969
And last, Presidio Heights, October 11 1969
I'm going to go away now and stick my head in a bucket of cold water, before emailing my friendly, downtown statistician...