About three-quarters of a mile from his residence, six months earlier, on Friday, April 10th 1970, Barbara Bates Keenan (42) was found shot dead with a .22 caliber gun in the kitchen of her 8 La Campana, Orinda home at approximately 3:45 pm by her 14-year-old daughter, Margaret. She had suffered two bullet wounds to her head and one to her back in an apparently motiveless attack. She had the cord from a steam iron wrapped around her neck, having apparently been struck on the back of the head with it also. However, it was concluded at autopsy that strangulation wasn't the cause of death. There was no signs of robbery and she had not been sexually molested. Investigators believed that the murderer knew the victim. Her husband, Oakland Insurance Executive Harold F. Keenan (45) was not a suspect in her murder.
The Zodiac Killer may have targeted Diane Kennedy Pike in a letter to the San Jose Police Department on November 21st 1969 and Daniel Williams for two weeks beginning on October 23rd 1969. Diane Kennedy Pike was an American writer and educator who lived in San Jose at the time this threatening letter was mailed. She was a school teacher at Willow Glen High School in San Jose between 1962 and 1964. Daniel Williams was a Salesian High School teacher in the city of Richmond, living at 1234 Bush Street in Martinez when he was threatened by a series of malicious phone calls just before the arrival of the Dripping Pen card..Both the phone caller and letter writer claimed they were the Zodiac Killer.
I am not suggesting that the Zodiac Killer had any hand in the murder of Barbara Keenan, but as an avid newspaper consumer, had the Zodiac Killer read about the murder on April 10th 1970 in any publication and chosen to target Edward C. Adams six months later, who lived just 3,730 feet from the residence of Barbara Keenan? If Edward C. Adams was aware of the murder in his neighborhood, then the out-of-the-blue threat on him and his family stating "you are next" may have engendered a higher degree of gravitas. By targeting the Adamses in Orinda so close to a brutal murder just six months earlier, it's possible the Zodiac Killer was hoping that investigators may consider his involvement in the unsolved murder of Barbara Keenan. In terms of topography, both residences are heavily shrouded with trees on Google maps. Whether this was the case in 1970 I am unsure. The Zodiac Killer never outright claimed his involvement in the attacks on Richard Radetich, Donna Lass, Kathie Snoozy & Debra Furlong, and Cheri Jo Bates by name, but insinuated his participation - so it's possible - in this instance - he had hoped that the statement of "you are next" to Edward C. Adams may have pushed investigators to consider him a suspect in a recent and local previous murder - that of Barbara Bates Keenan. If Edward C. Adams and Barbara Keenan were known to each other, the threatening postcard on October 17th 1970 would have had greater significance.