Tool Marks What are tool marks?What are tool marks? How can tool marks help make a case?How can tool marks help make a case? If you and I own identical pry bars, how can a forensic scientist identify which one was used at a crime scene?If you and I own identical pry bars, how can a forensic scientist identify which one was used at a crime scene?

2 Types of Characteristics 1.Class characteristics 1.Common to a group of objects 2.Example: A hammer has a distinctive shape and size. 2.Individual characteristics 1.Unique to a given object 2.Causes? 3.Example: shoes

Types of Tool Mark Impressions 1.Static (“impressed”) marks –Caused by a harder object being pressed into another softer object –Example: crow bar into wood 2.Dynamic (“striated”) marks –Caused when a tool slides or scratches across another surface –Example: sliding a key along the side of a car (Locard?)

Types of Tool Mark Impressions, cont… 3.Cutting (“crushed”) marks –Caused by pressure being applied to both sides of an object –Examples: pliers or wire cutters 4.Multi-stroke marks –Caused by repetitive actions –Example: a saw moving back and forth

Collecting Tool Mark Evidence What do you think the FIRST step would be?What do you think the FIRST step would be? 2 nd step:2 nd step: –Bagged and taken to lab for further analysis, if possible –Make a cast of the marks, usually with silicone rubber. What do you do with a recovered, suspect tool?What do you do with a recovered, suspect tool?

Examination of a Suspect Tool Step 1: ?Step 1: ? Step 2: ?Step 2: ? Make test marks with the tool.Make test marks with the tool. What piece of equipment would you use to compare the marks made in the lab with the marks made at the scene?What piece of equipment would you use to compare the marks made in the lab with the marks made at the scene? What other evidence can be obtained from a suspect tool?What other evidence can be obtained from a suspect tool?

Case Study Leah and Milton Rosenthal: icrosites/S/science/society/forensic _marks.htmlLeah and Milton Rosenthal: icrosites/S/science/society/forensic _marks.html icrosites/S/science/society/forensic _marks.html icrosites/S/science/society/forensic _marks.html The Lindbergh KidnappingThe Lindbergh Kidnapping

March 1, st ransom note, left at the scene:1 st ransom note, left at the scene: Dear Sir, Have $50000 ready, $25000 in $20 bills, $15000 in $10 bills and $10000 in $5 bills. After 2-4 days, we will inform you where to deliver the money.

More Ransom Notes March 6 th (postmarked in Brooklyn): increased to $70,000March 6 th (postmarked in Brooklyn): increased to $70,000 March 8 th : received by the Lindberghs’ attorney, refusing an intermediary and requesting a note in the paperMarch 8 th : received by the Lindberghs’ attorney, refusing an intermediary and requesting a note in the paper Retired principal John Condon printed offer in the paper to be the intermediary, and received an “acceptance” letter on March 9thRetired principal John Condon printed offer in the paper to be the intermediary, and received an “acceptance” letter on March 9th

More Ransom Notes March 10 th : Condon received the ransom money. Negotiations continued through the newspapers. March 12 th : 5 th ransom note delivered by cab driver, stating location of note #6.

More Ransom Notes Condon met with “John” in a cemetery to discuss ransom payment, and requested proof od child’s identity. March 16 th : Note #7 and a baby’s sleeping suit were received by Dr. Condon.

More Ransom Notes March 21 st : 8 th note demands complete compliance; said kidnapping had been planned for a year. March 30 th : 9 th note threatened to increase ransom to $100,000 April 1 st : 10 th note said to have money ready the next night

More Ransom Notes April 2 nd : Taxi driver delivered #11, giving location of #12 Dr. Condon met with “John” as instructed, handed him the $50,000 ransom, and was told the baby could be found on a boat named “Nellie” near Martha’s Vineyard.

FOUND!!! May 12, 1932 Badly decomposed and partially buried, about 4 ½ miles from home Death caused by a blow to the head Had been dead about 2 months

Enter Arthur Koehler, Forest Service Identified the types of wood and tool marks on the crudely made ladder