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Applying Modern Investigation Methods to Solve Cold Cases

Date Published
March 17, 2022

Behind every long-term missing person or unsolved murder case is a family who continues to look for answers. As the months and years pass by, these families live in a cruel limbo of mourning and hoping for answers that may never come.

Law enforcement agencies faced with investigating these long-unsolved cases must address both practical and philosophical considerations before doing so.

On the practical side, agencies must first determine their need: What types of cold cases are awaiting resolution and how many are there? Second, do agency detectives have the necessary skillset and access to resources to investigate these cases?

Lastly, law enforcement is also forced to wrestle with the philosophical aspect of cold cases: at what point do law enforcement and society move on from an unresolved murder or a long-term missing person?

As an investigator with the Cook County Sheriff’s Office, I believe that someone who was lost many years ago is no less important than someone lost today.

Identifying the Victims of John Wayne Gacy

In 2011, the Cook County Sheriff’s Office reopened the infamous John Wayne Gacy case after we learned that eight of Gacy’s 33 victims were never identified following the discovery of their bodies at Gacy’s Chicago residence in 1978.

When this information came to light in 2011, Cook County Sheriff Tom Dart and I discussed at length reopening the case. We concluded that, due to the heinous nature of the crimes, these victims were deeply deserving of another chance at identification.

Over the past 10 years, we’ve been able to identify three of the eight unidentified Gacy victims, and as of November 2021, we believe we are close to identifying others. Additionally, as a result of re-opening the Gacy case, we’ve been able to close 11 other cold cases involving missing persons that fit the profile of a Gacy victim. In five of those 11 cases, we were able to find the individual alive and reunite them with their families. In the other six cases, we found that the individuals were murdered by other men or died from other causes, effectively assisting other agencies with their death investigation or murder case.

Our success with clearing these cold cases has been directly tied to leveraging contemporary investigative methods in the analysis of decades-old evidence.

Forensic testing, specifically DNA analysis, is one of the most important tools we’ve relied on that was not available to our predecessors. But we’ve also had success utilizing the FBI’s Violent Criminal Apprehension Program (VICAP) and NIJ’s National Missing and Unidentified Persons System (NamUs), among others.

Applying these modern investigative methods to cold cases is an important step toward success in clearing them. But law enforcement agencies across the country can also improve their results in solving some of the hardest cases that come across an investigator’s desk by allocating resources efficiently through agency partnerships and prioritizing cases based on solvability.

Cold Cases, Contemporary Methods

Cold case units should deploy modern investigative methods and new scientific technology whenever possible.

New technologies and investigative practices can not only further a case and hopefully lead to a resolution, but they can also provide the families of victims with reassurance that law enforcement continues to search for answers.

If there is evidence that can be submitted to forensic laboratories, whether it be clothing or fingerprints, agencies should do so as soon as possible and compare the results with the databases currently available to law enforcement.

For example, if a case includes fingerprint evidence from 1990, we would resubmit that for laboratory analysis since the FBI recently implemented its Next Generation Identification system, expanding the power of its analysis.

Not only is it critical to submit dated evidence for an initial round of forensic testing, but re-testing evidence should also be considered due to how quickly the power and sensitivity of scientific analysis evolves.

There’s no rule of thumb on how much time should have passed before re-testing evidence. It’s all dependent upon what the results of the first analysis showed. For example, if DNA analysis from eight to nine years ago showed a good mitochondrial DNA profile, but the nuclear DNA was a little light, it might be a good time to re-test since the scientific capabilities have improved over the last decade.

The tools available today may certainly further the case by clearing and closing it, but oftentimes you will still conclude that the case remains unresolved. In these instances, the benefit comes from knowing that all of the evidence and information you’ve re-evaluated and that you’ve entered into the investigative repositories will now live on in perpetuity for future investigators.

I describe this as moving a case to a ‘contemporary status.’ Although the case isn’t resolved, this action adds investigative integrity to the case and provides value for the families of victims in knowing what is being done to further the investigation. When I sit with a family and tell them that their daughter’s murder from decades ago is still unsolved, but discuss what we’ve done to make it current and how evidence will now be continually compared to new information that comes to light, it’s almost as if they’ve won the lottery.

Simply moving a case to a ‘contemporary status’ gives us the best chance at providing families an answer because they carry the burden of having a loved one murdered or missing and not knowing what happened to them.

Finding Support for Cold Case Units

One of the biggest hurdles facing investigators with cold cases is convincing agency decision-makers and area lawmakers that it’s worthwhile to dedicate resources to these investigations.

That’s a critical first step in the success of any cold case investigation — dedicating staff to look into an old case.

Oftentimes, agencies will assign their detectives a current caseload and then ask that in their spare time they look at an old murder case.

In my opinion, that model does not work well. Instead, making progress on cold cases relies upon an active cold case unit or task force with detectives specifically assigned to these types of investigations.

Now, not every police department in the country can realistically develop a cold case unit. For example, Cook County, Illinois is the second largest county in the country and has about 130 police departments within its borders. Many of these departments are in small towns and may only have one unresolved murder case or one missing person case. That’s clearly not enough for these departments to form their own cold case unit. It’s unrealistic for a smaller department to take one or two of its only three detectives and dedicate them to work cold cases for months at a time.

However, when we combine all of the cold cases in Cook County, or any large jurisdiction, and add up every unsolved case from each respective law enforcement agency, we have a significant caseload that needs our attention. From here, agencies can combine their resources to form a county-wide or regional task force. This opens up opportunities for the larger agencies within the county or area to provide unique resources and a different skillset to these investigations. Also, combining forces allows the assigned investigators to see patterns not previously known due to agencies not sharing case information.

This is important because cold case investigations require a specific skillset and knowledge base that is unlike many other investigations. Detectives assigned to cold cases should have a background in death investigation, be well-versed in how to obtain old records, and know the limitations and possibilities of scientific testing methods. For example, if you can read an old pathology report and identify what new technology is out there that may expand upon prior test results, that’s critical in a cold case investigation.

Lastly, every cold case detective must learn to be patient. If you resubmit evidence and the new testing actually gives you a DNA profile, but there’s no hit in available databases, you didn’t solve the case. However, obtaining that DNA profile is still a huge win in a cold case investigation.

Prioritizing Cases Based on Solvability

In addition to clearing unsolved cases, cold case units may also serve as a crime deterrent. Criminals must know that they are going to be pursued until the day they die if they take someone else’s life. It’s not over in six months or a year because the case has yet to be solved. These criminals will have to look over their shoulder for the rest of their life.

However, there’s a reason that cold cases weren’t solved the first time around.

To start, they’re often hard cases to solve. There are also certain limitations unique to each case, and there could have been mistakes made during the initial investigation.

When you talk about solvability in a cold case setting, you’re looking for two things: evidence and documents.

When evaluating cold case files, specifically look for evidence that could benefit from modern investigative methods and forensic testing. In some instances, you’ll unfortunately find that the evidence collected in a case is gone. There may have been a theft, or a fire or flood that destroyed an inventory room and damaged evidence. In other cases, I’ve read police documents from the 1960s and 1970s where police leaders believed a case to be investigated to the fullest extent and discarded evidence because they needed the space to store files from other cases.

Now, this wasn’t done maliciously — investigators had exhausted all investigative leads available to them at the time, and they just weren’t thinking of new scientific methods that were to come along decades later.

In the Gacy case, we had very detailed documents, which included the skeletal analysis, dental reports, and the layout of Gacy’s home where the remains were recovered. The evidence piece was located within the remains of the victims. In order to bring in contemporary investigative techniques, such as DNA analysis, we performed a series of exhumations to obtain the necessary biological material for testing.

Cases that contain extensive evidence for analysis and documents for review like those in the Gacy case are obviously closer to being solved than those lacking these particular pieces of evidence and documentation.

The Value of Cold Case Investigative Teams

It’s an unnatural status for a person to remain missing for months and years. As citizens, we shouldn’t accept it when a person disappears for many years.

What does it mean for our community to have long-term missing persons? Does it mean there’s human trafficking in the area, or are we not addressing mental health properly and people go on to live a homeless, drug-addicted life? Is there a serial killer on the loose?

There are many reasons to be concerned about communities experiencing a significant number of long-term unsolved cases. It’s a sign of an unhealthy society and cold case units provide the necessary support for law enforcement agencies to begin clearing these cases.

Cold case units help ensure every unsolved case is reviewed using the latest and most effective investigative methods. Even if the case isn’t immediately cleared through modern methods and forensic analysis, we’ve brought the case to a contemporary status. The evidence and biometrics are now sitting in a place where they’ll be continually compared to new data in the future.

That’s valuable, not only for law enforcement, but for the families of victims who continue to look for answers. These victims and their families should not be forgotten without an attempt to bring about a resolution into their disappearance or murder.

About Notes From the Field

The National Institute of Justice (NIJ) is the research, development, and evaluation arm of the U.S. Department of Justice. NIJ aims to address the critical questions of the criminal justice field, particularly at the state and local levels.

NIJ posts the Notes From the Field series to allow leading voices in the field to share their strategies for responding to the most pressing issues on America’s streets today.

Notes From the Field is not a research-based publication. Instead, it presents lessons learned by on-the-ground criminal justice leaders, from years of experience and thinking deeply about criminal justice issues.

Date Published: March 17, 2022