Featured Research

from universities, journals, and other organizations

Using Telltale Toolmarks To Fight Crime

Date:
April 14, 2004
Source:
Ames Laboratory
Summary:
Law enforcement has a new tool to help bring criminals to justice, thanks to research by scientists at the U.S. Department of Energy's Ames Laboratory.

This image of an American Eagle on a Sacagawea dollar resulted from a scan by a profilometer. The scan is used to create a contour map that illustrates the detail and resolution that can be produced by the instrument.
Credit: Image courtesy Ames Laboratory

AMES, Iowa – Law enforcement has a new tool to help bring criminals to justice, thanks to research by scientists at the U.S. Department of Energy's Ames Laboratory.

When tools such as screwdrivers, pliers and wire cutters are manufactured, the manufacturing process leaves certain imperfections, or patterns, embedded in the tools' surfaces. Because these patterns are believed to be unique for each tool, when criminals use them to perpetrate crimes, such as jimmying a door to gain access to a location, the patterns on the tools are often transferred to the crime scene.

In the past, investigators have been able to help the courts convict criminals by visually matching the marks on tools to crime scenes. But this technique is under attack. In a landmark 2000 case, a Florida court deemed a toolmark inadmissible, saying the "proposition of uniqueness" for a knife blade based on marks transferred to a victim was a scientific theory that had been inadequately tested by the scientific community.

Two research projects at the Ames Laboratory have responded to the challenge in an attempt to establish toolmark uniqueness. The first project, spearheaded by Stan Bajic, Ames Laboratory associate scientist, and David Baldwin, director of the Laboratory's Midwest Forensics Resource Center, involved building a database of toolmark images and developing an algorithm to statistically analyze the images. The database consists of digital images of marks on tool surfaces left during six different manufacturing processes.

Building of the database required the production of multiple images using a forensic comparison microscope. Researchers included numerous tools in their research, from screwdrivers, pliers and wire cutters to bolt cutters, tin snips, cold chisels, wood chisels and pry bars. An unprecedented 13,000 images have been produced for the database.

The images produced were used in the development of a software tool for the reduction and analysis of the image data. Algorithms were developed and used for comparison of the various toolmarks by Max Morris, Ames Laboratory associate and Iowa State University professor of statistics and industrial engineering, and Zhigang Zhou, a graduate student in statistics. Morris' software can mimic the behavior of the forensic examiners.

"Our preliminary results have been very encouraging," said Morris. "In the vast majority of cases, the algorithm correctly identifies images taken from different surfaces as non-matches. It also correctly identifies most pairs of images taken from a common surface as matches." Morris calls the results "an important first step" in the effort to develop tools to determine the uniqueness of toolmarks."

In a third research project, Scott Chumbley, an Ames Laboratory metallurgist and ISU professor of materials science and engineering, is taking toolmark analysis from the two-dimensional to three-dimensional level. Chumbley and co-principal investigator Larry Genalo are using 3-D characterization methods and statistical methods to identify toolmarks. Their research involves using a profilometer, a scanning tool that measures the height or depth of toolmarks, and then develops a type of contour map of the marks from the scan.

The map can then be used to precisely identify a toolmark, allowing forensic specialists to match the mark on the tool to the marks made by the tool at the crime scene. According to Chumbley, "Preliminary results show the reproducibility of the instrument is better than 99.9 percent on known samples."

Ames Laboratory is operated for the Department of Energy by Iowa State University. The Lab conducts research into various areas of national concern, including energy resources, high-speed computer design, environmental cleanup and restoration, and the synthesis and study of new materials.


Story Source:

The above story is based on materials provided by Ames Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Ames Laboratory. "Using Telltale Toolmarks To Fight Crime." ScienceDaily. ScienceDaily, 14 April 2004. <www.sciencedaily.com/releases/2004/04/040414004703.htm>.
Ames Laboratory. (2004, April 14). Using Telltale Toolmarks To Fight Crime. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2004/04/040414004703.htm
Ames Laboratory. "Using Telltale Toolmarks To Fight Crime." ScienceDaily. www.sciencedaily.com/releases/2004/04/040414004703.htm (accessed August 21, 2014).

Share This




More Matter & Energy News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Flower Power! Dandelions Make Car Tires?

Flower Power! Dandelions Make Car Tires?

Reuters - Business Video Online (Aug. 20, 2014) Forget rolling on rubber, could car drivers soon be traveling on tires made from dandelions? Teams of scientists are racing to breed a type of the yellow flower whose taproot has a milky fluid with tire-grade rubber particles in it. As Joanna Partridge reports, global tire makers are investing millions in research into a new tire source. Video provided by Reuters
Powered by NewsLook.com
Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

AFP (Aug. 19, 2014) A solar cell that resembles a flower is offering a new take on green energy in Japan, where one scientist is searching for renewables that look good. Duration: 01:29 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins