The Disappearance of Corinne June Groenenberg, November 1973
On Thursday, November 1, 1973, Corinne Groenenberg, 16, left her family's residence in Modesto, Stanislaus County, CA. A family friend told authorities that they saw Corinne walk to the highway and begin hitchhiking shortly afterwards. The family friend saw Corinne enter a blue or green truck with an unidentified male driver.
According to an update from the Charley Project on September 15, 2025, Corinne was carrying a sleeping bag and a "red Indian blanket" when she was last seen. She was also wearing a blue denim jacket and blue jeans.
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| Corinne Groenenberg. Photo from NamUs. |
Corinne is a 5'6, 115 lbs white female with straight brown hair and blue eyes. She has a strawberry birthmark on her back, as well as a surgical scar on her abdomen. Corinne was born on either October 4, 1959 (making her 14 at the time) or October 14, 1957 (making her 16); most agencies list her as 16 at the time of her disappearance. Some agencies may list her first name as Connie.
Corinne's family had moved from southern CA to the Modesto area several weeks before her disappearance. According to the Charley Project, "Corinne's mother was diagnosed with scleroderma, a rare and severe tissue disease, shortly after Corinne vanished. Her parents were forced to move as a result of her mother's condition. Corinne's parents have continued to own her childhood home. Her mother said that they hoped Corinne might return to see her former residence."
Corinne's DNA and dental records are available for comparison, while her fingerprints are not. NamUs states that Corinne has 20 rule-outs, however she in fact has 19, as one of the entries in her exclusion list is blank. One of the UIDs found in WA has since been identified as Elisabeth "Lisa" Roberts.
Corinne is classified as Endangered Missing on the Doe Network and Charley Project. Her NamUs case, #MP4547, was created on January 6, 2010 and last updated September 17, 2025.
Anyone with information regarding Corinne's disappearance is urged to contact Police Civilian Investigator Bonn Panyanouvong of the Modesto Police Department at (209) 572-9500 or police@modestogov.com. The agency case number is 89016305.
Furthermore,
according to the CA DOJ's missing persons database, "If you think you
know the whereabouts of any person, BEFORE TAKING ANY ACTION, please
contact the law enforcement agency listed in the record, or the
California Department of Justice at 1-800-222-FIND (24 hour nationwide
toll-free Hotline) or (916) 210-3119, or email us [CA DOJ] at
missing.persons@doj.ca.gov." According to the same site, individuals
seeking to contact CA DOJ regarding a missing person can use the email
form here.
Corinne's case has been mentioned before in a Zodiac forum, which is where I found out about it. In my opinion, her disappearance resembles the cases known as the Santa Rosa Hitchhiker Murders, so I have tagged it accordingly despite not having been mentioned as such online before. Corinne physically resembles and is a similar age as many of the victims, who were killed in 1972-3 after being picked up while hitchhiking in northern CA.
Note: Corinne went missing the day after Halloween, also known as All Saints' Day, as well as El Dia de los Muertos to people of Mexican descent. The day after Corinne went missing, November 2nd, is also known as All Souls' Day. See the Holiday & Events Reference Page for an explanation as to why this is being mentioned.
Sources
Modesto Police Department, archived
The Tulare Advance-Register 5/31/02
The Modesto Bee 6/1/02, 6/20/04, 2/13/06
National Missing Persons Directory
Stanislaus Area Crimestoppers, archived
International Missing Persons wiki
Whereabouts Still Unknown blog
List of general CA cases, ZK Ciphers forum
Note: While this write-up was originally published on June 23, 2025, I regularly revisit cases, fix any typos or formatting errors, check for updates, hyperlink new posts, ensure that I have exhausted all sources, etc., and then make note of when I last did so, no matter how minor. When edits are extensive, I re-post the write-up entirely. This post was last updated on October 26, 2025.
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