California Astrological Murders

One thing I always wondered about is if serial killers tend to escalate their crimes. Doing worse and worse things. Like Jack the Ripper.
BTK started with the Oteros? A whole family. Is that really supposed to be the start of his "career"?
I really dont think the Zodiac stopped.
Astrological Murders - California
Between December 1969 and November 1970, police in Northern California linked nine unsolved murders with a single perpetrator, still at large. A common bond is found in the disposal of the bodies, cast off in ravines, and in the killer's hypothetical obsession with astrology. Of nine acknowledged victims , seven died in fair proximity to a seasonal solstice or equinox, while two were slain on Friday the thirteenth. Additionally, it is possible the murders may have lasted through December 1973, with six more victims added to the body count.
The list begins, officially, with one Leona Roberts, found ten days before the winter solstice, in December 1969. Her death was treated as a homicide, although the cause is listed as "exposure" by the medical examiner.
The killer had a busy month in March of 1970, beginning with Cosette Ellison, found nude in a ravine seventeen days before the vernal equinox, the cause of death undetermined. Two days later, on March 5, Patricia King was strangled and discarded, naked, in a rural gully. Nurse Judith Hikari vanished on March 7, thirteen days before the equinox; she was discovered, nude and bludgeoned in an overgrown ravine, on April 26. On Friday, March 13, Marie Anstey was kidnapped in Vallejo, stunned by a blow to the head, and then drowned; her body was recovered in rural Lake County, on March 21, and an autopsy revealed traces of mescaline in her bloodstream. Celebrating the equinox itself, on March 20, the slayer clubbed Eva Blau to death and dumped her body in a roadside gully; once again, the medical examiner found drugs in the victim's system.
The seventh victim on official rosters is a nurse named Donna Lass, abducted from Lake Tahoe prior to the autumnal equinox, on September 26, 1970. Her body has never been found. Nancy Bennallack appeared to break the killer's pattern, dying with her throat cut in a Sacramento flat October 26, but she remains on the official roster. Number nine was Carol Hilburn, a Sacramento X-ray technician, found beaten to death in a ravine on Friday, November 13. She had been stripped except for one boot and the panties that her killer left around her knees.
http://www.skcentral.com/articles.php?article_id=528
At least of those have been suspected of being Zodiac victims. I wonder if they have really linked all those nine to a single perpetrator?
In that case these victims really should be looked into more. And the astrological murders.
Anyone that knows more about the link? Are they officially linked? Based upon what?

I agree that Zodiac did likely keep killing, as he himself indicated in his counts.

In October he says he has killed 7, but then in the 12/20/69 Belli letter he mentions possibly getting a 9th and 10th victim. So who was #8? Roberts perhaps? Or Betsy Aardsma on 11/28/69?

Then on 4/20/70 he says he has killed 10.

So who were #8 and #9?

I think Hakari and maybe Anstey or one of the others.

These possible "Astrological" crimes also blend into the Sonoma County cases like Kim Wendy Allen, Jeanete Kamehele and the others.

See:

http://www.santarosahitchhikermurders.com/

And:

http://www.santarosahitchhikermurders.com/zodiac.html