I have had great opportunities over my many years in law enforcement. I have served as a police officer, a deputy sheriff, and even the chief deputy, but I found my greatest career opportunity at the Minnesota Bureau of Criminal Apprehension (BCA). At BCA, I tackled my most challenging assignment when I led the Cold Case Unit (CCU).
Early in my career, I gained valuable experience by working on homicide teams. But, studying the errors of others and reworking an old case granted me even greater insight into why cases fail. This article describes one of the major sources of these investigative errors: a phenomenon I dubbed the "Disease of Certainty."
The Disease of Certainty is fatal to investigations. Both inexperienced and seasoned officers can catch this contagious disease, and it can spread throughout a team. It occurs when officers feel so convinced of their own beliefs that they allow themselves to become tunnel-visioned about one conclusion and ignore clues that might point them in another direction. Those who resist the disease may be ridiculed and ostracized for their supposed lack of understanding and inability to see the truth if all of their coworkers share the same beliefs and assumptions about the investigation.
The numerous cases that CCU worked over the years taught us many lessons about the Disease of Certainty. For clarification, when I refer to the BCA CCU, I include all members of the BCA team (agents, analysts, forensic scientists, and support personnel) and the local and county investigators who assist these investigations. Cold case investigations demand a multiagency approach to solve a difficult problem, so a diverse set of personnel with varying expertise comprise the team.
By describing what 1 have learned about the Disease of Certainty, I do not aim to demean the work of the initial agencies involved, but to help others avoid the same mistakes in the future. I want to eliminate this deadly disease of perception that can prevent investigators from seeing beyond their own assumptions. All of these cases involved dedicated and professional individuals, but fatal errors occurred nonetheless. CCU does not aim to judge the initial investigators but to work with the agency as a team to reinvigorate the investigation. One person or agency never deserves all of the credit for cracking a case because it demands a true team effort.
A Case Study
My work with CCU began with numerous rape and assault cases, but I will focus on a series of homicides. The first of the confirmed homicides occurred in December 1978. As the Huling family slept in their secluded rural farm house north of the Twin Cities (St. Paul and Minneapolis) in Minnesota, an intruder entered their home. Before leaving, the intruder viciously murdered Alice Huling and three of her children--miraculously, one survived.
Several other seemingly unrelated crimes occurred over the following year. The next one took place in May 1979 when Marlys Wohlenhaus came home from school. A few hours later, her mother returned from errands and...