Overview

Last Seen: June 5, 1974, during the early morning hours.

Location: Concord House, Concord, Jefferson County, Wisconsin, near Interstate 94.

Circumstances: Catherine attended an Oconomowoc High School prom/post-prom celebration. After reportedly arguing with her boyfriend, she left the Concord House alone at approximately 3:00 a.m. and disappeared.

Key Points: Catherine had upcoming commitments and her family did not believe she intended to run away. No confirmed trace of her has been discovered. Later speculation concerning convicted murderer Edward Wayne Edwards was investigated, but authorities said they did not believe he was responsible. Catherine remains listed as missing and endangered, and investigators continue to seek information.

Detailed Case Breakdown

The Disappearance of Catherine Lynne Sjoberg: Wisconsin’s Unsolved 1974 Prom-Night Mystery

More than five decades after Catherine “Cathy” Lynne Sjoberg disappeared after an Oconomowoc High School prom celebration in Jefferson County, Wisconsin, her case remains unsolved. Catherine vanished during the early morning hours of June 5, 1974, after leaving the Concord House, a dance hall and banquet facility near Interstate 94 in Concord.

Catherine has never been found, and authorities continue to classify her as a missing and endangered person.

A Prom Night That Ended in a Disappearance

Catherine was an Oconomowoc High School student who attended her school’s prom celebration in June 1974. The festivities eventually moved to a post-prom gathering at the Concord House in rural Jefferson County.

At approximately 3:00 a.m., Catherine reportedly had a disagreement with her boyfriend and left the building. Accounts describe her as walking outside alone, either to get some fresh air or after becoming upset during the disagreement.

A friend reportedly saw Catherine leaving the building. It became the last confirmed sighting of her.

Catherine was dressed for prom, making her disappearance especially striking. Descriptions indicate she wore a long, light-blue formal gown with floral details, along with a corsage and high-heeled shoes. She had brown hair and green eyes and stood approximately 5 feet 5 inches tall.

She never returned to the party and was never seen or heard from again.

Catherine Was Not Expected Home Immediately

Catherine’s absence did not initially trigger an immediate missing-person alarm because her mother, Ruth Schwartz, reportedly believed Catherine planned to stay with a friend following the prom festivities.

When Catherine failed to return and her boyfriend came looking for her, concern grew.

Her family maintained that voluntarily disappearing did not fit Catherine’s behavior or plans. She had important events approaching, including high school graduation activities, and was reportedly expected to serve as maid of honor at a family wedding.

Those circumstances contributed to her family’s longstanding belief that Catherine did not simply decide to run away.

The Investigation

The Jefferson County Sheriff’s Office investigated Catherine’s disappearance and interviewed people connected with the prom and the events surrounding her last known movements.

Despite searches, interviews and reported possible sightings over the years, investigators did not locate Catherine or establish conclusively what happened after she left the Concord House.

Her disappearance eventually became one of Wisconsin’s longstanding cold cases.

The circumstances became even more unsettling several years later when another young couple disappeared after attending an event at the same location.

The Concord House Connection

In August 1980, 19-year-olds Timothy Hack and Kelly Drew disappeared after attending a wedding reception at the Concord House.

Their bodies were discovered weeks later in a wooded area. The similarities naturally generated questions about whether their murders and Catherine’s disappearance might somehow be connected.

Years later, investigators obtained DNA evidence linking Edward Wayne Edwards to the Hack-Drew murders. Edwards, a convicted killer who had once worked around the Concord House property, was arrested in 2009 and ultimately convicted of killing Hack and Drew.

The development briefly raised hopes within Catherine’s family that the same man might have been responsible for her disappearance.

Investigators, however, said they did not believe Edwards was responsible for Catherine’s disappearance. Authorities reportedly determined that Edwards was not in Wisconsin when Catherine vanished in 1974.

No evidence publicly released by investigators has established a connection between Edwards and Catherine’s case.

A Family Waiting for Answers

Catherine’s family spent decades hoping to discover what happened to her.

In 1995, 21 years after she disappeared, her mother held a memorial service for Catherine at a church in Oconomowoc. The service gave the family an opportunity to mourn, but there were no remains to bury and no definitive answer about Catherine’s fate.

When the Hack-Drew murder case was solved decades later, Catherine’s relatives again hoped the development might provide answers. Investigators’ conclusion that Edwards was apparently not involved left the central mystery unchanged.

Someone still may know what happened after Catherine walked away from the Concord House that night.

Latest Publicly Available Investigation Information

Catherine remains listed as a missing endangered person by the Wisconsin Department of Justice Clearinghouse for Missing & Exploited Children & Adults. The state listing continues to direct anyone with information to the Jefferson County Sheriff’s Office.

The National Center for Missing & Exploited Children also maintains an active missing-person poster for Catherine and displays an age-progressed image showing how she might have appeared later in life.

A 2022 examination of the case by The Deck, produced with case materials that included information attributed to the Jefferson County Sheriff’s Office, identified a Jefferson County detective contact and emphasized that investigators were still seeking information concerning Catherine’s disappearance.

More recent public case databases continue to carry Catherine as missing. Missing People in America updated its Catherine Sjoberg case entry in April 2025 and continues to direct tips to the Jefferson County Sheriff’s Office.

As of September 2026, publicly accessible official records reviewed for this article do not announce an arrest, identification of Catherine’s remains, confirmed suspect, or resolution of her disappearance. Her Wisconsin DOJ listing remains active.

The absence of a publicly announced breakthrough does not necessarily mean investigative work has stopped. It means no newer substantive development could be verified through the publicly available sources reviewed.

What Happened to Catherine Sjoberg?

The crucial unanswered question remains what happened immediately after Catherine walked out of the Concord House.

She was a teenager alone in formal clothing during the early morning hours in a rural area. Whether she encountered someone outside, accepted a ride, attempted to walk somewhere, or was the victim of a crime has never been publicly established.

More than 50 years later, even seemingly insignificant information could potentially matter. A memory from someone who attended the prom, knowledge passed down within a family, information about a vehicle seen near the Concord House, or something once dismissed as rumor could provide investigators with another avenue to examine.

Catherine Lynne Sjoberg has been missing since June 5, 1974.

Anyone with information should contact the Jefferson County Sheriff’s Office.

Very Brief Case Summary

Last Seen: June 5, 1974, during the early morning hours.

Location: Concord House, Concord, Jefferson County, Wisconsin, near Interstate 94.

Circumstances: Catherine attended an Oconomowoc High School prom/post-prom celebration. After reportedly arguing with her boyfriend, she left the Concord House alone at approximately 3:00 a.m. and disappeared.

Key Points: Catherine had upcoming commitments and her family did not believe she intended to run away. No confirmed trace of her has been discovered. Later speculation concerning convicted murderer Edward Wayne Edwards was investigated, but authorities said they did not believe he was responsible. Catherine remains listed as missing and endangered, and investigators continue to seek information.