In a letter in 1969, Zodiac wrote: "I shall change the way the collecting of slaves. I shall no longer announce to anyone when I comitt my murders, they shall look like routine robberies, killings of anger, & a few fake accidents, etc." In 1974, Zodiac claimed that he had killed 37 people (there are only six confirmed Zodiac victims). Author Robert Graysmith, throughout his years investigating the Zodiac case, developed a theory about who the remainder of Zodiac's victims were. The theory initially stemmed from the observation that in the known Zodiac killings, there seemed to be some sort of focus on the passenger side of the victims' cars. Passenger door windows were open and many of the bodies were found either hanging out of the front passenger door or on the ground near the door. It is even possible that Zodiac was positioning the bodies in this way in some sort of a ritualistic fashion, associating the passenger side of the car with hitchhikers. This, in turn, prompted Graysmith to investigate some of the other unsolved murders in the Bay Area and Northern California during this time frame. Almost all of the following murder victims were hitchhikers. The killer had a knot tying consistent with a seaman. Remember, Zodiac was likely a military, probably Navy, man. Many of these victims were found near areas of water, as most Zodiac victims had been. Few had been sexually molested and none of the clothing of the nude victims has ever been found. The killer struck over weekends at dusk or night and bound a couple of his victims with white clothesline similar to that used at Zodiac's Lake Berryessa attack. Many of these attacks came on or near astrologically significant dates, such as solstices and equinoxes. Follow this link for more information regarding Zodiac and why he killed when he did. Some of Zodiac's possible victims include: - Donna Lass, the Lake Tahoe nurse last seen alive just before the Autumnal Equinox. Lass' body has never been found and she is strongly considered to be a Zodiac victim. - Judith Ann Hikari, also a nurse, whos body was found on April 26, 1970, in a shallow grave in Placer County. - Nancy Bennallack, a court reporter, who was found dead in her apartment on Oct. 26, 1970. The next day the Chronicle received a letter from Zodiac claiming 14 victims. Police felt that if Zodiac did indeed kill Lass, he might be responsible for the deaths of the other two victims. The list continued: - Marie Antoinette Anstey was abducted from the Coronado Inn in Vallejo, where Darlene Ferrin used to go dancing. This was seven days before the Vernal Equinox on Friday, March 13, 1970. One year to the day after she disappeared, Zodiac mailed the Chronicle a letter. One year to the day that her body was discovered, March 21, 1971, Zodiac mailed the Chronicle a postcard. - Carol Beth Hilburn, another nurse and Santa Rosa resident, was also killed on a Friday the 13th, this time in November of 1970. On the northern edge of Sacramento, a car pulled off Ascot Avenue and drove 30 feet into a field, dragging Hilburn's body through the weeds and throwing it face up next to a wire fence. The victim's throat had been cut and she was so badly beaten that dental records were necessary to establish her identity. The day before, a mysterious girl known only as "Dee" accompanied Carol to Sacramento to see some friends who were members of a local motorcycle gang. Dee dropped Carol off at an after-hours club on West Capital Avenue frequented by motorcycle gangs. The name of the club was the Zodiac. She was last seen at the bar at 4 a.m. When her body was found the next day, she was wearing only one suede boot and her panties had been pulled down around one knee. - Nancy Patricia Gidley was also killed on a Friday the 13th, this time in San Francisco. She was abducted from her hotel and dumped in the parking lot of Washington High School. All of her clothes had been taken. Paul Stine, the cabdriver, had been killed on Washington St. - Cosette Ellison was killed on March 3, 1970, 17 days before the Vernal Equinox. Patricia King was killed two days later. Eva Blau was killed on the Vernal Equinox. All were tossed in ravines. In 1969, Leona Roberts had been killed ten days before the Winter Solstice. Police believe that one man killed all these women. Even more linked crimes were undiscovered. The most intriguing series with pertinence to the Zodiac case took place in Santa Rosa over the course of seven years: - Maureen Sterling and Yvonne Weber, both 12 years old, vanished on their way home from the Redwood Ice Skating Rink in Santa Rosa at 4 p.m. on Friday, Feb. 4, 1972. Their skeletons were discovered down a 60-foot embankment off a rural road in the Franz Valley area of east Sonoma County. They had been murdered elsewhere and dumped at this site. They were discovered on Dec. 28, 1972. The killer had kept their clothes and had also taken one gold earring from each girl. - Kim Wendy Allen, a 19-year-old Santa Rosa Junior College student, vanished while hitchhiking to her residence in Santa Rosa on March 4, 1972. She was seen hitchhiking north on Highway 101 at about 5 p.m. It was a Saturday, and 16 days before the Vernal Equinox. Her nude body was found in a creekbed 20 feet from Enterprise Road. She had been strangled with white clothesline; her wrists and ankles show marks of having been bound as if she had been spread-eagled. She was superficial cuts on her chest. One of her gold earrings had been taken as well as her clothes and possessions. She was also carring with her a wooden barrel with the word "soy" printed on it. Also on the barrel was a Chinese character which strongly resembles a character drawn by the Zodiac in the April 24, 1974 "Exorcist" letter. The killer kept the barrel. - Lori Lee Kursa, 13, was last seen alive in the U-Save Market in Santa Rosa on Nov. 21, 1972. Her nude body was found on Dec. 12, 1972, with a broken neck. She had two wire loops in her pierced ears, no earrings attached. - Carolyn Nadine Davis, 15, was last seen leaving her grandmother's house in Garberville on July 15, 1973, hitchhiking south on 101. She was a runaway from Anderson in Shasta County. Her nude body was discovered 2.2 miles north of Porter Creek Road on Franz Valley Road in the same exact spot as Sterling and Weber. She was found on July 31, 1973. The police discovered that Carolyn had bought a one-way ticket to fly from Redding to San Francisco. She had been poisened by strychnine. - Therese Dian Walsh, 23, disappeared exactly on the Winter Solstice of 1973, hitchhiking on 101 from Malibu Beach to her home in Garberville. Her body was discovered near the spot where Kim Wendy Allen's was found. She had been hog-tied with a one-quarter-inch nylon rope, strangled and thrown into a creek. She had been sexually assaulted. - Jeannette Kamahele, 20, was found on July 6, 1979. A Santa Rosa Junior College student, she was last seen hitchhiking near the Cotati on-ramp of Highway 101 and was traveling north to Santa Rosa on April 25, 1972. Her body was discovered in a Sonoma County ravine in a shallow grave near Calistoga Road. The coed had been tied with her hands and ankles bound to her neck; white clothesline was wrapped around her neck four times. She was found 100 yards from the spot where Lori Lee Kursa's body was discovered. There were even more possible Zodiac victims. Betty Cloer, 21, was killed two days before the Summer Solstice in 1971. In 1972, Linda Ohlig, 19, was murdered six days after the Vernal Equinox and Alexandra Clery, 24, was killed 18 days before the Autumnal Equinox. Susan McLaughlin, 19, was murdered 18 days before the Vernal Equinox and Yvonne Quilantang, 15, 11 days before the Summer Solstice in 1973. Nineteen days prior to the Winter Solstice, both Cathy Fechtel, 27, and Michael Shane, 30, were killed and dumped off a Livermoore Highway. Six days after the Autumnal Equinox in 1974, Donna Marie Braun, 14, was murdered. On Thursday, Oct. 16, 1975, Susan Dye was strangled while she was hitchhiking home. She was discovered under a freeway overpass near Santa Rosa. Even if these victims were not the work of the Zodiac, there was definitely a pattern of serial murder occurring in Northern California during the first half of the 1970s. A report issued from the California Dept. of Justice in 1975 stated that "over the past five years (1969-1974), there have been fourteen young women murdered in Northern California, and all of these murders appear to have been committed by the same person. Eight other women have mysteriously disappeared in the states of Oregon and Washington over the past year." The report concluded that "the murders will probably continue until such time as the perpetrator is identified and apprehended." For a very intriguing timetable which compares and possibly links one of the prime Zodiac suspects and this series of murders, follow this link.