Ten years ago, when I was a captain with the Illinois State Police, the investigation into the Stacy Peterson disappearance fell squarely into my lap.

On the morning of October 28, 2007, Stacy sent a text message to a friend and was never heard from again. Her case made international news, undoubtedly because her husband, Drew Peterson, was a sergeant in the Bolingbrook Police Department at the time.

Shortly after Stacy disappeared, I addressed the media and identified Drew as a suspect in her disappearance. It was the first time the Illinois State Police ever made such a bold assertion in an ongoing criminal investigation. I thought then – and still believe – that Drew is the only suspect in her disappearance.

Stacy Disappears and Drew Peterson Points to “Another Man”

To put things in perspective, thousands of people are reported missing to the police each year in the United States. A missing person is anyone whose location is unknown for reasons that cannot be explained – a very broad definition, but one that is necessary because not all missing people are the victims of a crime.

Investigators must quickly search for evidence that suggests a person has fallen victim to a crime. A disappearance is often the first indicator that a serious crime has occurred.

When Stacy’s sister, Cassandra Cales, filed the missing person’s report, the reasons for Stacy’s disappearance were unknown and could not be explained. It did not make sense that Stacy would leave her young children with her husband from whom she was growing apart.

However, Drew quickly explained away Stacy’s disappearance, claiming she left with another man and was where she wanted to be. But in my opinion, the information we gathered did not support his claims.

An Exhaustive Search Begins

We undertook a number of investigative tasks to try to solve Stacy’s disappearance. We interviewed family members and friends, searched residences and vehicles, canvassed neighborhoods, analyzed cell phone records, notified border crossing officials, set up credit card usage alerts, and obtained Stacy’s DNA profile, fingerprints and dental records.

We also recognized the need to develop a sound strategy to search for Stacy’s body. Based on our investigation, we determined the search area would be on land – including residential and light industrial areas as well as forest preserves — and in the water – small ponds, drainage areas and the Chicago Sanitary and Ship Canal.

Patrol Captain Ken Kaupas’ “Circle”

My colleague Ken Kaupas – an Illinois State Police patrol captain who is now deceased — volunteered to develop a search strategy and determine the area in which Stacy’s body was most likely to be found. Kaupas’ idea provided a framework for the search group to work with.

Kaupas’ process was relatively simple. He placed Stacy’s home at the center of the search area because it was the last place Stacy was seen alive.

From there, Kaupas plotted every location known to the investigation that was somehow tied to Stacy. The Joliet Junior College, where Stacy attended nursing class. The home address of a former high school friend, with whom Stacy had recently been spending time. The areas identified from Drew and Stacy’s cell phone pings on the night of Stacy’s disappearance. The location data gleaned from the Illinois Tollway transponder from Stacy’s car. Even the distance traveled by a weighted blue barrel thrown into the canal.

Hundreds of locations were plotted onto a circular map with Stacy’s Bolingbrook home as Ground Zero. In the end, the map revealed clusters of locations to search, but none of the data points extended beyond 25 miles.

Based on that data, Kaupas suggested that if Stacy’s body were ever located, it would be within 25 miles of Ground Zero. With that, the term “Kaupas Circle” was born.

kaupas circle

Peterson’s Conviction for Murder – and the Unfinished Search for Stacy

Even though Stacy Peterson’s body was never found, I believe the conceptual strategy Kaupas developed may someday help solve Stacy’s disappearance and could be used as a framework for other law enforcement agencies working missing-person cases.

In 2012 – five years after Stacy’s disappearance – Drew was convicted of killing his third wife, Kathleen Savio.

I believe justice for Stacy is next.



Photo Credit: Tribune photo by E. Jason Wambsgans