Dados de entrada

The following is a listing of items that might be submitted for examination with the results that may be determined.

Possible Types of

Evidence Possible Examinations/Determinations

Projectile Caliber

Weapon type

Possible manufacturer Cartridge case Caliber

Weapon type

Possible manufacturer Possible reload

Entry into NIBIN database

Multiple projectiles Same as projectile – plus if fired from same firearm or multiple firearms

Multiple cartridge cases

Same as cartridge case – plus if fired from same firearm or multiple firearms

Fired projectile or Cartridge case and firearm

If fired from or in the submitted firearm

Shot pellets / shot wads

Size of shot pellets Gauge of shotgun Gauge of wad

Possible pellet size contained in wad

Clothing and firearm Approximate distance weapon was from clothing* Clothing and shotgun Approximate distance shotgun was from clothing* Firearm General condition and if mechanically functional

Amount of pressure required to release hammer or firing pin Restoration of obliterated serial numbers

Determination of illegal modifications

Test firing to obtain test specimens for comparison

Test fire for acquisition into the NIBIN database (comparison to other shooting incidents)

[08/08/2014] PEH-02-09: 5 of 7

The most current copy of The Physical Evidence Handbook is available at: http://www.txdps.state.tx.us

Version: 04

Firearms and Toolmarks Evidence

TOOLMARK EXAMINATION

Manufacturing processes and use cause tools to bear unique microscopic characteristics. Under certain conditions these characteristics can be imparted to surfaces contacted by tools. Submitted tools should be able to produce the mark in question and have a suspect associated with them.

If it is not possible to submit the evidence, a cast of the mark may be submitted. It is recommended, however, that the evidence mark be submitted whenever possible. Photographs locate toolmarks but are of no value for identification purposes.

Possible Examinations

Toolmark

With Suspected Tool

Determine if Submitted Tool Produced the Mark/Cut

Without Suspected Tool No Examination

Occasionally items are submitted that may exhibit multiple marks or cuts (doorframes, doors, cut wire, etc.). In this event, it is extremely important that the evidence marks in question are properly identified. This can be done in various ways. Marks on doors, etc. can be clearly photographed with the appropriate marks designated. Wires can be taped with the appropriate markings on the tapes. The important consideration is to make sure that the evidence mark in question is analyzed.

DPS does not analyze biological items, such as bone, cartilage, skin, etc., for the purpose of determining if a particular sharp object, such as a knife, may have been used. If you need assistance in locating a laboratory that does this type of examination, contact your local DPS Firearms lab for a list of possible labs.

[08/08/2014] PEH-02-09: 6 of 7

The most current copy of The Physical Evidence Handbook is available at: http://www.txdps.state.tx.us

Firearms and Toolmarks Evidence

Evidence must be clearly identified as to the location of the actual evidence markings. If the evidence is to be removed (i.e. cut wire to be collected for examination), clearly identify either the evidence toolmark or the non-evidence toolmark side prior to removing the physical evidence from its origin. It is also helpful to indicate in the submission documents or on the evidence packaging how the evidence/non-evidence toolmarks are designated (i.e., “non-evidence ends of wire covered with evidence tape”).

Range of Conclusions

Firearms and Toolmarks reports will contain some or all of the following conclusions. The interpretation of individualization/identification is subjective in nature, founded on scientific principles and based on the examiner’s training and experience. The statement that “sufficient agreement” exists between two toolmarks means that the agreement is of a quantity and quality that the likelihood another tool could have made the mark is so remote as to be considered a practical impossibility.

Identification: Agreement of a combination of individual characteristics and all discernible

class characteristics where the extent of agreement exceeds that which can occur in the comparison of toolmarks made by different tools and is consistent with the agreement demonstrated by toolmarks known to have been produced by the same tool.

Inconclusive:

A. Some agreement of individual characteristics and all discernible class characteristics, but insufficient for an identification

B. Agreement of all discernible class characteristics without agreement or disagreement of individual characteristics due to an absence, insufficiency, or lack of reproducibility

C. Agreement of all discernable class characteristics and disagreement of individual characteristics, but insufficient for an elimination

Elimination:

Significant disagreement of discernible class characteristics and/or individual characteristics

Unsuitable:

Unsuitable for examination

[08/08/2014] PEH-02-09: 7 of 7

The most current copy of The Physical Evidence Handbook is available at: http://www.txdps.state.tx.us

Firearms and ToolmarksEvidence

Preparer

Forrest W. Davis Date: 07/23/2014

Quality Assurance Coordinator

Concurrence

D. Pat Johnson Date: 08/04/2014

Laboratory Director

Version # Effective

Date Brief Description of Change(s) 00 05/04/2007 Original Issue

01 07/09/2010 Major Revision – Introduction , Firearms Examination, NIBIN

02 05/16/2012 Major Revision – Introduction, Firearms Examination, Toolmark Examination, NIBIN

03 10/16/2012 Major Revision – NIBIN practice change, Range of Conclusions 04 08/08/2014 Minor Revision – Toolmark Examination, NIBIN

[08/08/2014]

The most current copy of The Physical Evidence Handbook is available at: http://www.txdps.state.tx.us

NIBIN Evidence