Case Solved With Aid of Fracture Match

Robert E. Kramer; Detective
Police Division – 220 Clay Street – Cedar Falls, IA 50613
(319) 268-5132

Just after 3:00 am on a warm summer morning in 1996 the Cedar Falls Police received a call of a reported bomb threat at a distributing warehouse near the South edge of the city. A worker had been in the parking lot having a cigarette when he walked past his car and noticed a note under the windshield wiper. He reported the suspicious note to his supervisors inside the plant and plant officials then called the police. Upon arrival, the entire warehouse was evacuated. The note, written on an 8-1/2″ X 11″ piece of paper torn from a spiral notebook read: “I have placed a bomb in the warehouse and you’ll never find it.” As a precaution, workers were kept from re-entering the plant until a bomb sniffing K-9 and handler drove 60 miles from Cedar Rapids, Iowa to search the facility. Deliveries were also prevented from leaving the plant, and the business lost over $15,000.00 in sales for the day.

I had been called in to work and unrelated incident earlier in the morning, and upon finishing my assignment at that scene I drove to the distributing warehouse. The plant had already been evacuated, witnesses were being interviewed, and the K-9 team was nearly on the scene. I had an opportunity to examine the piece of notebook paper on which the threat was written. (The possibility of recovering fingerprints from the paper was realized, so protective gloves were worn.) The message was written in what appeared to be blue ball point ink. It also appeared that the hand-printing was purposely disguised, and this, I thought was odd. The man who discovered the note was giving a statement to a supervisor at the scene, and I had an opportunity to overhear some of the conversation they were having. During this time I asked the man who found the note if I could have permission to look inside his vehicle, as I suspected that whoever planted the note may have left behind other evidence. The vehicle owner told me that he had discovered his drivers side door unlocked when he came out for the cigarette, but believed there was nothing missing from the vehicle.

Inside the vehicle I found a spiral notebook folder similar to what most of us have used in the past for school work. I had the feeling immediately that the bomb threat may have been written on a piece of paper which was then torn from the notebook. The notebook was seized as evidence. I was hoping at the time that I would be able to connect the bomb threat with the notebook, and also possibly recover fingerprints of the suspect/s from the notebook. Later in the day at the Crime Lab I carefully paged through the notebook and did in fact find a 1.5 cm piece of paper lodged in the spiral. This piece of paper was identified as having originally been part of the bomb threat page by conducting careful fracture match analysis between this small piece and the larger bomb threat page. (See photo illustration.)


I am not typing this article for the purpose of singing praises as to some special feat of police work which was conducted in discovering the small piece of paper which connected the bomb threat note to the notebook in the reporting person’s car. Rather – I want to describe the rather simple means taken to photograph the exhibits side by side. Handling the piece of paper which was found lodged in the spiral of the notebook was difficult. I’d thought at first that I could aid the handling process with tweezers, but soon discovered that indents produced in the exhibit from the tips of the tweezers could be seen under the high magnification which I was planning to use in the photo process. The handling was all but eliminated when I figured out (quite by accident) the means I was going to use in positioning the two paper exhibits side by side and in such close proximity.

I first positioned a 16″ X 20″ piece flat black colored paper on the base of the MP4 camera stand in the Lab. Atop this paper was placed an 8-1/2″ X 11″ piece of glass from a picture frame. I then placed the 1.5 cm piece of paper atop this piece of glass and sandwiched it with a second piece of picture frame glass. This alone offered me a means of sliding the small piece of paper around without handling it. I then positioned the bomb threat page atop the second piece of glass in such a position that it was “close” to being in position which would allow the fracture match to be illustrated. You guessed it – a third piece of glass was placed atop the exhibits which truly sandwiched them together. Sliding the pieces of glass atop one another was simple and with almost no effort, I was able to illustrate the two papers nearly pieced together.

Photographing the two exhibits was quite simple. Taking the magnification into consideration, I knew that I would have to have a certain degree of depth of filed in the finished print. Once proper exposure was obtained, I found that the picture shown above (taken at 1/30th second – f/16) allowed the exhibits to appear as if they were on the same plane. No flash was used to take the picture. The exhibits were illuminated with the four flood lamps of the lab camera stand.