Overview

Last seen: November 1, 1973
Location: Modesto, California
Status: Missing; case remains open
NamUs: MP4547
Modesto Police case: 89016305
NCIC: M-378718501
Doe Network: 931DFCA

Main circumstances: Corinne left her family’s residence and was observed heading toward a highway. According to the available case accounts, she began hitchhiking and was last seen entering a blue or green truck driven by an unidentified White male. No confirmed contact with Corinne has been reported since.

Detailed Case Breakdown

Corinne June Groenenberg: The 1973 Disappearance of a Teenager in Modesto, California

Corinne June Groenenberg disappeared from Modesto, California, on November 1, 1973, after reportedly leaving her family’s residence, walking toward a highway and hitchhiking. A family friend told authorities that Corinne was last seen getting into a blue or green truck driven by an unidentified White man. She has never been heard from again. More than five decades later, her disappearance remains an open missing-person case.

Brief Case Summary

Last seen: November 1, 1973
Location: Modesto, California
Status: Missing; case remains open
NamUs: MP4547
Modesto Police case: 89016305
NCIC: M-378718501
Doe Network: 931DFCA

Main circumstances: Corinne left her family’s residence and was observed heading toward a highway. According to the available case accounts, she began hitchhiking and was last seen entering a blue or green truck driven by an unidentified White male. No confirmed contact with Corinne has been reported since.

Who Was Corinne June Groenenberg?

Corinne was a teenager with brown hair and blue eyes who stood approximately 5 feet 6 inches tall and weighed about 115 pounds. Identifying features include a strawberry-type birthmark on her back and a surgical scar on her abdomen. Dental records are available.

There is an important discrepancy in public records concerning Corinne’s age and birth date. The current California Department of Justice listing gives her date of birth as October 14, 1957, which would make her 16 when she disappeared. NamUs-derived records likewise identify her as 16. The Charley Project, however, lists October 4, 1959 and an age of 14. Because the official California record and NamUs-derived information support the older age, it is safest to describe Corinne as approximately 16 years old, while noting the conflicting historical records.

The Disappearance on November 1, 1973

Corinne’s family had moved to the Modesto area from Southern California only weeks or months before her disappearance. On November 1, 1973, Corinne left the family’s residence. A friend reportedly saw her walking toward a highway and followed or observed her until she began hitchhiking.

The precise highway is not identified in currently available official case information. That distinction matters because some secondary accounts have introduced conflicting geographical details over the years.

The last reported sighting placed Corinne getting into a blue or green truck. Its driver was described only as an unidentified White male. No publicly available description establishes his identity, age, name or relationship—if any—to Corinne.

That encounter is the central event in Corinne’s disappearance. She was never confirmed to have reached another destination and has never been heard from again.

What Corinne Was Carrying

Later case information provides additional details about what Corinne may have had with her.

The Charley Project lists her clothing as a blue denim jacket and blue jeans and says she was carrying a red Indian blanket and a sleeping bag. Solve the Case’s updated record contains the same information.

Those possessions may suggest she anticipated traveling or being away from home, but the public record does not establish her intended destination. It would therefore be speculative to conclude from the blanket and sleeping bag that she planned to permanently run away.

The Search for Corinne

The Modesto Police Department remains the investigating agency. California’s Attorney General continues to maintain Corinne in its missing-person database under case number 89016305, listing her as last seen in Modesto on November 1, 1973.

Corinne is also represented in NamUs-derived databases as MP4547. Her Doe Network identifier is 931DFCA. An older Websleuths case discussion reproducing agency information lists NCIC M-378718501.

DNA and dental information are reported as available for comparison purposes. This is particularly important in a decades-old disappearance because such records can be used when investigators evaluate unidentified remains.

A Family That Continued Waiting

Corinne’s disappearance profoundly affected her family. Her mother, Doreen, was diagnosed with scleroderma shortly after Corinne vanished, and the family eventually left the Modesto area. According to historical accounts summarized by The Charley Project, Corinne’s parents continued to maintain ownership of her childhood Southern California home because they held onto the possibility that she might someday return there.

A 2002 Associated Press account later reproduced in the Websleuths discussion described Corinne’s parents as still hoping for information nearly three decades after she vanished.

Possible Connections and Unidentified-Person Comparisons

Over the years, amateur investigators and missing-person researchers have proposed comparisons between Corinne and unidentified women found in different parts of the United States. These discussions can help generate leads, but they should not be mistaken for official determinations.

For example, Websleuths users have discussed Corinne as a possible comparison for unidentified remains in several cases. At least one historical unidentified-person comparison list records Corinne as having been excluded through DNA.

There has also been online speculation about whether Corinne’s disappearance could somehow relate to other teenagers who vanished from the Modesto area in the 1970s. No credible public law-enforcement source located for this article establishes such a connection.

Latest Investigation Information

The most recent publicly accessible information located during research continues to characterize Corinne’s disappearance as an open case.

The California Department of Justice still carries Corinne in its missing-person database and directs information to the Modesto Police Department.

The Charley Project most recently updated its Corinne Groenenberg entry on September 15, 2025, adding or revising information concerning her clothing and the circumstances of her disappearance.

Solve the Case lists the case as open and shows its case page as last updated January 7, 2026. That database also reports that DNA and dental information are available.

No publicly documented arrest, identified suspect, confirmed recovery of Corinne’s remains, or resolution of her disappearance was located in the current sources reviewed for this article. The unidentified man driving the blue or green truck therefore remains one of the most significant unanswered elements in the publicly known case.

More Than 50 Years Without an Answer

Corinne June Groenenberg disappeared during an era when hitchhiking was considerably more common and decades before today’s network of surveillance cameras, mobile-phone location records, digital communications and modern national missing-person databases.

Yet several potentially valuable pieces of information have survived: her photograph, physical description, identifying marks, dental information, reported DNA availability, the description of what she was wearing and carrying, and the witness account placing her in a blue or green truck.

More than half a century later, the essential question has not changed: Who was driving the truck that picked up Corinne Groenenberg on November 1, 1973, and what happened after she got inside?

Anyone with information should contact the Modesto Police Department rather than attempting to investigate or confront a person independently.