Overview

Last Seen: August 15, 1993
Last Seen Location: Wishek/rural Logan County, North Dakota
Kristin’s Age: 30
Missing With: Robert Michael “Bob” Anderson
Vehicle Recovered: August 20, 1993, Aberdeen, South Dakota
Current Status: Missing; authorities believe Diede and Anderson were homicide victims
NamUs: MP29972

Main Circumstances

No one has been publicly convicted of their presumed killings, and the case remains unsolved.

Diede and Anderson traveled from Minnesota to North Dakota with Diede’s children.

They were dealing with a dispute concerning the children before disappearing.

They spoke with a North Dakota Highway Patrol trooper about child-custody issues on August 15.

Both disappeared after being seen in the Wishek area that day.

Their Dodge van was found abandoned in Aberdeen, South Dakota, five days later.

Neither Diede nor Anderson has been located.

Their remains have not publicly been identified or recovered.

North Dakota authorities believe they were victims of homicide.

Detailed Case Breakdown

Kristin Joy Diede and Robert Michael Anderson: The Unsolved 1993 North Dakota Disappearance

More than three decades after Kristin Joy Diede and Robert Michael “Bob” Anderson disappeared during a trip to North Dakota, investigators still have not publicly identified what happened to the couple or recovered their remains. What began as a missing-person investigation has become one of North Dakota’s enduring cold cases, with authorities stating that they believe Diede and Anderson were victims of homicide.

Kristin Joy Diede and Bob Anderson Travel to North Dakota

Kristin Joy Diede was 30 years old when she disappeared in August 1993. She was living in Bloomington, Minnesota, and was in the process of a divorce. Diede traveled with her boyfriend, Robert Michael Anderson, to the Wishek, North Dakota, area with her two children.

On August 15, Diede and Anderson dropped the children off with their paternal grandparents. According to later accounts, the couple encountered difficulty when they attempted to retrieve the children. Before disappearing, Diede and Anderson also spoke with a North Dakota Highway Patrol trooper about child-custody laws. They reportedly indicated that they planned to collect the children and return to Minnesota.

Diede and Anderson were last seen in the Wishek area on August 15, 1993. Neither has been heard from since.

The Couple’s Van Is Found in Aberdeen, South Dakota

Five days after the couple was last seen, their Dodge van surfaced more than 100 miles away in Aberdeen, South Dakota.

The vehicle was reported abandoned in a railroad-area parking lot on August 20, 1993. A later examination of the case by Dakota Spotlight reported that the van was discovered without license plates. The vehicle ultimately became evidence and was being held in Logan County, North Dakota, when the investigative series revisited the case.

The van created a central mystery that remains unanswered: how did a vehicle associated with two people last seen near Wishek end up abandoned in Aberdeen while Diede and Anderson seemingly disappeared without a trace?

Early Missing-Person Reports and Investigative Questions

One complication highlighted by later reporting involved the initial handling of the disappearances.

Friends and relatives in Minnesota contacted authorities after realizing Diede and Anderson were missing. However, Dakota Spotlight and InForum reported that the early reports apparently did not result in a comparable immediate missing-person report being made to North Dakota authorities. The North Dakota Attorney General’s current cold-case summary states that Diede was reported missing on August 26, 1993.

Authorities initially considered the possibility that the couple had voluntarily left. Diede’s loved ones rejected that explanation, particularly because they did not believe she would abandon her children. Over time, the investigation took a much darker direction.

Why Investigators Believe Kristin Diede and Bob Anderson Were Killed

No bodies have been recovered, but North Dakota authorities now publicly state that Diede and Anderson are believed to have been homicide victims. Their disappearance is featured on the North Dakota Attorney General’s cold-case page, and Kristin remains listed in North Dakota’s missing-person database.

Several circumstances have contributed to the continuing suspicion surrounding the case: the couple vanished abruptly after saying they intended to return to Minnesota, they left their possessions behind, and their van appeared abandoned in another state only days later. No confirmed subsequent sightings have established that either person remained alive after August 15, 1993.

Those facts do not establish who was responsible or precisely where or how the couple died. No one has been convicted of killing Diede or Anderson.

Domestic Violence and the Circumstances Before Kristin Disappeared

Later investigative reporting also examined Diede’s troubled marriage and events preceding her disappearance.

Dakota Spotlight reported that Diede’s marriage had deteriorated and that her estranged husband had previously been convicted of domestic assault involving her. The podcast reported that a judge imposed a two-year no-contact order. Friends interviewed for the series described Diede as fearful during the period before she disappeared.

These circumstances have received significant attention in subsequent examinations of the case. They are part of the investigative history, but they should not be confused with proof of responsibility for Diede and Anderson’s disappearance. The case remains unsolved, and publicly available law-enforcement records do not identify a person who has been convicted or charged with their presumed homicides.

A Case Spanning Minnesota, North Dakota and South Dakota

One reason the investigation is unusually complicated is its geographic scope.

Diede and Anderson lived in Minnesota. Their last known movements occurred around Wishek in south-central North Dakota. Their vehicle was then discovered in Aberdeen, South Dakota. That sequence created an investigation involving events and potential evidence spread across three states.

In 2016, Anderson’s family and a website dedicated to the case announced a $5,000 reward for the discovery of human remains confirmed as belonging to either Anderson or Diede. The appeal specifically encouraged hunters, farmers, surveyors and others traveling through the countryside between the Wishek and Aberdeen areas to remain alert for potential evidence.

Renewed Investigation and the Vanishing Act Series

The disappearance received renewed attention in 2022 through Dakota Spotlight: Vanishing Act — The Untold Story of Kristin Joy Diede and Bob Anderson, an 11-part investigative series.

Journalists James Wolner and Jeremy Fugleberg reconstructed the couple’s final days, interviewed relatives and friends, examined historical documents, revisited locations connected to the disappearance and explored competing theories about what could have happened. The series also revisited the abandoned van and examined why the disappearance received comparatively little attention when it occurred.

The series presented theories to a retired North Dakota homicide detective, but those theories should not be treated as established findings. They illustrate unanswered investigative possibilities rather than conclusions reached in court.

Latest Information on the Kristin Joy Diede Investigation

As of 2026, there has been no publicly announced arrest or resolution in the disappearance of Kristin Joy Diede and Robert Michael Anderson.

North Dakota’s current missing-person database continues to list Kristin Joy Diede, with the Logan County Sheriff’s Office identified as the investigating agency. The North Dakota Attorney General also continues to publish the Diede-Anderson case among the state’s cold cases and states that the pair are believed to have been homicide victims.

There have also been recent updates to independent missing-person records. The Doe Network recorded an update to Diede’s case file, 4166DFND, on January 2, 2026. The Charley Project’s companion page for Robert Anderson was updated February 4, 2026. Neither update announced that the case had been solved.

More than 30 years after the couple vanished, the fundamental questions remain unchanged: what happened after Kristin Diede and Bob Anderson were last seen on August 15, 1993, who transported their van to Aberdeen, and where are they now?

The Logan County Sheriff’s Office continues to be the primary agency identified for information concerning the case. Anyone with credible information about the disappearance should provide it directly to law enforcement.

Very Brief Case Summary

Last Seen: August 15, 1993
Last Seen Location: Wishek/rural Logan County, North Dakota
Kristin’s Age: 30
Missing With: Robert Michael “Bob” Anderson
Vehicle Recovered: August 20, 1993, Aberdeen, South Dakota
Current Status: Missing; authorities believe Diede and Anderson were homicide victims
NamUs: MP29972

Main Circumstances

No one has been publicly convicted of their presumed killings, and the case remains unsolved.

Diede and Anderson traveled from Minnesota to North Dakota with Diede’s children.

They were dealing with a dispute concerning the children before disappearing.

They spoke with a North Dakota Highway Patrol trooper about child-custody issues on August 15.

Both disappeared after being seen in the Wishek area that day.

Their Dodge van was found abandoned in Aberdeen, South Dakota, five days later.

Neither Diede nor Anderson has been located.

Their remains have not publicly been identified or recovered.

North Dakota authorities believe they were victims of homicide.