Evidence Collection Guidelines - Toolmarks

Impression Evidence Student Notes:

Crime Scene Investigator Network

Evidence Collection Guidelines - Toolmarks

Nature of Evidence

Preservation and Packaging of Tools

Make No Tests with Tools

Preservation of Tool Marks

Alaska Scientific Crime Detection Laboratory User’s Guide

Toolmarks p 28

Toolmark Nomenclature & Definitions

Tool –

Toolmark –

Cast -

Capabilities & Services

Examinations of the tool mark prior to the recovery of a suspect tool: (what info can the laboratory provide?)

Examination of the Suspect tool with a toolmark

Provides class characteristics by –

Several test marks are made and

Possible Conclusions:

Collection Guidelines – Toolmarks

Collection of Tools

Mike Byrd, Miami-Dade Police Department Crime Scene Investigations

Other Impression Evidence

Plastic Prints -

Tool Marks –

Recovering 3D Impressions -

Rhode Island State Crime Laboratory

Operations-Submission Manual

Impression Evidence p. 25

How impressions are made

Collection of Impression Evidence

Dwane S. Hilderbrand, CLPE
Lead Latent Print Examiner, Scottsdale Police Crime Lab

Footwear Impression Evidence

When properly collected and preserved, what can footwear impression evidence prove or disprove?

Four basic methods of recording footwear impressions

Lifting Latent Prints

Electrostatic dust lifter -

Casting Plastic Impressions

Why Cast?

Admissibility of Footwear Evidence

Impression Evidence Student Notes:

Crime Scene Investigator Network

LATENT FINGERPRINTS

What are fingerprints?

The latent print section performs what duties?

AFIS

Collection Guidelines:

If you choose to field process (powder, superglue, etc.) your own items or scene, please take in consideration proper procedures and methods for these processes.

Packaging

Photography

Latent prints should be photographed with

Known Prints:

Known prints or known exemplars are

Crime Scene Investigator Network

Evidence Collection Guidelines

Latent Fingerprints

Preservation of Fingerprint Evidence

Primary precaution in all cases is
Most prints will be on
Although the use of cloth to pick up exhibits prevents leaving prints, the cloth will

Papers and documents should be

Rhode Island Crime Laboratory

p. 14

LATENT PRINTS

Latent prints are among

The lab may be able to

Collection and Submission of Evidence:

Packaging/Identification

Identify all evidence, indicating if it is an

All photographic and digital images of latent prints must include

Exposure to water or dampness

Submission of Known Exemplar Prints for Comparison

Identifying the Deceased

Automated Fingerprint Identification System (AFIS)

Unidentified Latent Prints

Impression Evidence Student Notes:

Crime Scene Investigator Network

Evidence Collection Guidelines - Toolmarks

Nature of Evidence

Tool marks are encountered most frequently in burglary cases but may also be found in other types of crimes. The evidence consists of striations or impressions left by tools on objects at the crime scene and various types of tools found in the possession of suspects. In other cases, it is possible by means of physical and other comparisons to prove that parts of tools left at crimescenes were broken from damaged tools found in the possession of suspects. In many cases, it is possible to identify the specific tool which made the questioned marks by means of a Laboratory comparison of tools and marked objects. In some instances, it is also possible to prove that marks of various types on tools were produced by objects which they contacted at crime scene.

Preservation and Packaging of Tools

All areas on recovered tools which contain transferred paint, building material, or other contamination should be wrapped in paper and packaged to prevent the prying blades or cutting edges from contacting any other surface or object.

Make No Tests With Tools

Attempts should never be made to fit tools into questioned marks or to make test marks prior to Laboratory examination. If done, the questioned mark or tool may be altered and this may make any Laboratory examination valueless. In addition, traces of transferred paint or other stains on the tool may be lost or additional material may be transferred to the tool.

Preservation of Tool Marks

Whenever possible, submit the whole object containing tool marks to the Laboratory instead of just removing the area containing the mark. If this is not possible, carefully photograph and sketch the area containing the mark. Although this photograph will not be sufficient to allow the Laboratory to perform a toolmark comparison with the tool, it will assist the Laboratory to determine how the mark was made so that test marks can be-more easily made.
Casts of tool marks can be made by a person who has had considerable experience in this work. Poor casts are useless for comparison purposes and some marks will be damaged if improper methods are used.
Pack the object containing tool marks so that no alteration or damage will occur during shipment. Small objects should be wrapped with clean paper and placed in envelopes or boxes, while important areas on larger objects can be protected with paper. Whole, large objects can be packed in cartons or crates, if not delivered in person.

Alaska Scientific Crime Detection Laboratory User’s Guide

Toolmarks p 28

Toolmark Nomenclature & Definitions

Tool - An object used to gain mechanical advantage; the harder of two objects which when brought into contact with each other, results in the softer one being marked.

Toolmark - A mark produced on a softer receiving surface by a harder object.

Cast- The reproduction of a toolmark or the surface of a tool using a molding material such as

silicone rubber, Mikrosil™, Forensic Kerr Permlastic™ or other suitable material.

Capabilities and Services

Examination of the tool mark prior to the recovery of a suspect tool:

The lab can provide valuable investigative information to the investigating officers through the careful examination of the toolmark. The possible determinations are as follows:

Type of tool used (class characteristics)
Size of tool used (class characteristics)
Unusual features of tool (Class and/or individual characteristics)
Action employed by tool in its operation
Most importantly, examination can determine if the toolmark is of value for identification purposes.

Examination of the Suspect tool with a toolmark

The tool will be examined for foreign deposits such as paint or metal for comparison against the marked object. This trace evidence may help associate the tool with the marked surface; however, the trace evidence in these circumstances usually provides class characteristics evidence.

After the examination for foreign material, class characteristics are compared to establish consistency. Finally, several test marks are made with the suspect tool, and microscopic comparisons of the test against the questioned toolmark are made. Three possible conclusions may be reached.

That the tool produced the toolmark
That the tool did not produce the toolmark
That there are not sufficient corresponding individual characteristics between the known and the unknown to determine if the tool did not did not produce the mark.

Collection Guidelines – Toolmarks (p. 29)

If the object bearing the toolmark is reasonably mobile, bring the entire object to the lab. Protect the toolmark area by covering it carefully with paper; however, always consider latent fingerprints when packaging. If the object is particularly large or is completely immobile, the toolmark area may be cut out (depending on the situation, e.g., security considerations and damage to property) or cast using a suitable casting material. Include mid-range or orientation photographs, sketches, and reports.

DO NOT place suspect tool into toolmark as it could destroy markings.

Discussion: The actual toolmark is preferred over a cast of the toolmark; therefore, the microscopic marks need to be protected to provide the best possible results. Placing the tool into the toolmark may destroy microscopic detail. Submission of photographs, sketches, and reports may help the examiner determine the action of the tool.

ITEM – Tools

Method - Package in a manner to protect the working end of the tool (e.g. on a screwdriver place a paper fold over the tip). After the working end has been protected, place in a rigid container.

Mike Byrd, Miami-Dade Police Department Crime Scene Investigations

Other Impression Evidence

Plastic Prints: 3D impressions having a length, width, and depth, are usually discovered outdoors in surfaces like dirt, sand, clay, mud, tar, or snow.

Tool Marks:

Usually found at areas of forced entry by cutting, prying, pinching, or sheering.

A rubber base or silicone impression material is used to recover the tool mark impression (we used clay)

The impression cast is packaged in a plastic container or small box for transportation to the lab.

Recovering Three dimensional Impressions

Casting – filling the 3D form with materialtht will duplicate and retain the characteristics of the impression.

Cast should be packaged in a sturdy box to protect it from cracking or breaking. Do not stack items on top of the box during transport.

Rhode Island State Crime Laboratory

Operations-Submission Manual

Impression Evidence p. 25

Persons committing a crime may leave footwear or tire impressions entering and/or exiting the crime scene. In many instances, impressions can be positively identified as having been made by a specific shoe or tire. Clothing of a pedestrian struck by a motor vehicle can also leave impressions on the vehicle. Examinations may provide investigative lead information such as brand and model of tires and footwear leaving impressions. Vehicle makes and models may also be determined from wheel base measurements of tire tracks.

Collection of Impression Evidence

Once detected, impression evidence should be photographed and collected as described below:

Take close-up photographs. 35 mm photography is preferred over digital photography for impression evidence. If digital photography must be used, it is recommended that the camera be set at the highest capture quality/resolution possible. Contact the laboratory for assistance in setting up your camera if needed. Poor image quality/resolution may adversely affect the comparison between the image and exemplar footwear. A scale must be included in these photographs so that an actual-size enlargement can be made. The camera must be directly above the impression, not at an angle. Submit the negatives, film, and or digital image to the laboratory.
If the impression evidence can be removed from the scene, protect the impression from possible damage before submitting it to the laboratory.
If the impression is three-dimensional (in sand, soil, or snow), cast the impression with Dental Stone. NOTE: Impressions in snow should be sprayed with snow wax before casting.
If the impression is two-dimensional and cannot be removed, then photograph and lift.
Do not cover an impression with tape. This may obliterate it and make enhancement impossible.
Do not attempt to wash a cast. Submit it to the laboratory with the soil intact.
Always photograph impression before attempting the cast/lift. Do not substitute one for the other.

Dwane S. Hilderbrand, CLPELead Latent Print Examiner, Scottsdale Police Crime Lab

Footwear Impression Evidence

It is necessary to determine and prove that a particular person or persons may or may not have been present at the scene of a crime. The collection, preservation, and analysis of physical evidence have become increasing important.

Criminals have become smarter by wearing protection over their hands to avoid leaving fingerprints and masks to avoid eyewitness identification, but they tend to make little attempt to conceal footwear.

(When properly collected and preserved, what can footwear evidence prove or disprove? )

When this type of evidence is properly collected and preserved by the crime scene investigator, followed up by detailed examination by a footwear expert, it can become an important part in proving or disproving a suspect was at the crime scene. Footwear evidence can lead to positive identification of which particular shoe made the print. Footwear evidence can provide investigators with certain information that can assist them in locating a suspect. Most footwear evidence, when collected and preserved properly can provide the type, make, description, approximate size, the number of suspects, the path through and away from the crime scene, the involvement of the evidence, and the events that occurred during the crime.

Search for footwear evidence and photographs should be completed before any other search is performed. Once the footwear impressions are identified and marked, complete documentation and photographing and casting can be completed later.

There are four basic methods of recording footwear impressions at the crime scene.

Photography
Documentation/Sketching
Casting
Lifting

Lifting Latent Prints

This lifting method works by placing the adhesive paper or contact paper, adhesive side down, over the impression in dust or light dirt and smoothing over. This will allow the impressions to be transferred to the adhesive side of the paper. Once this is done the paper is then peeled off the impression and photographed. The paper can be treated with a mixture of 0.05 grams of crystal violet to 500 ml. of distilled water which stains the footwear impression, but produces a reversed image when collected. Once this is completed a piece of clear acetate is placed over the print in order to preserve it for impounding and later examination purposes.

Latent fingerprint powders and lifting tapes can be used on various surfaces for contrast and recovery.

Many of the chemicals used by latent fingerprint examiners can be used to enhance the footwear prints on a variety of items.

Many latent footwear impressions can be located with the oblique lighting technique. Once found they can be difficult to photograph, but latent fingerprint powders can be used to build contrast for easy photography. This procedure is performed in the same manner as if you were dusting for latent fingerprints. Once the prints have been developed and photographed, the recovery process is the same using fingerprint lifting tapes and suitable contrast backgrounds to place the lift on. Never cover an impression with tape to reserve it until after the completion of the photographs. The tape will only obliterate the print and make subsequent enhancement difficult. Place the tape over the impression only after all other methods of enhancement have been exhausted. Make sure the footwear evidence was not placed in dust, as there may be more suitable methods of collection.

Since 1981, an excellent recovery method for visible and invisible footwear evidence has been widely used around the world and has resulted in footwear identifications. This technology is called the electrostatic dust lifter.

The system has a high voltage electrostatic charge that creates a charge on a piece of lifting film and causes some of the dust or residue particles to transfer to the underside of the lifting film. The system works on a wide variety of surfaces including, floors, doors, counter tops, chairs, fabric, metal, carpet tile, newspapers, bodies, tar and many others. The quality of the print is dependent upon the type of surface it is deposited on. No matter what the detail is that is recovered the crime scene investigator should always turn the print over to the examiner for examination.

Casting Plastic Impressions

Why Cast?

The cast gives lifelike and actual-size molding of the original impression including uneven surfaces and depths.
The cast gives reproduction of microscopic characteristics.
In deep impressions, the cast gives reproduction of characteristics of the side of outsolesand midsoles of the shoe which usually are not reproduced in photographs.
Focus or scale problems are eliminated.
Provides tangible 3-dimensional evidence.
Backs-up the photographs.

Admissibility of Footwear Evidence

"The role of the expert witness is not to determine guilt or innocence, but rather to assist the court in determining what weight is to be placed on technical evidence entered which without assistance could not be interpreted properly." (Cassidy, 1980)

The crime scene investigator should always approach the crime scene as if the attorney met you at the front door and told you, "tomorrow we are going to court." The best way to prepare for any trial is to be prepared for the unexpected.

If a thorough crime scene report is prepared, the crime scene investigator can describe the steps of the investigation chronologically. Remember, your reports and notes are subject to subpoena during a trial.

The crime scene investigator should understand the techniques and legal requirements necessary to ensure that the crime scene photographs and the evidence collected will be admissible in court.

The basic premise involved in crime scene photography is that the photographs are a true representation of the scene as it was initially observed by the investigator. Nothing will cause evidence to be tossed out of court faster by defense attorneys than no photographs of the footwear evidence prior to the crime scene investigator placing a scale in the photograph or not following proper procedures. Defense attorneys will argue that the evidence was altered.

Crime Scene Investigators are considered to be expert witnesses in the investigation of the crime scene. The expert witness is determined only by the court. The court will weigh the qualifications, experience, and demeanor of the investigator carefully every time that he/she appears. The expert witness is allowed to give an opinion on any relevant issue that is within the scope of their expertise.

Once the footwear evidence has been entered into evidence, the Footwear Examiner will take the stand to testify as to the examination or comparison procedures. Never allow yourself to become caught up in testifying to an examination or the comparison of footwear evidence unless you have been properly trained and possess the experience, qualifications and training of a footwear examiner.