PHYSICAL EVIDENCE MANUAL - Crime Scene Investigator Network

Physical Evidence Manual
Adopted: May 2002
Revisions: 6
Last Revision: January 31, 2008
1.0 PREFACE
The need for proper recognition, collection, and preservation of physical
evidence is mandated for use in the criminal justice system. Physical evidence
can directly or indirectly lead to the solution of a crime. Charging and prosecution
decisions may be affected by the quality of the physical evidence supporting the
case. United States Supreme Court and Oregon Supreme Court decisions have
placed great emphasis upon physical evidence in criminal cases.
The Oregon State Police (OSP) Forensic Services Division (FSD) provides an
important link between collection and court presentation of such evidence. It
sometimes happens, however, that materials submitted to the laboratory prove
inadequate for proper analysis or that improper collection or packaging methods
destroy valuable evidence.
A member of the Criminal Justice System may not know the proper way to collect
and preserve evidence in all situations he/she may encounter. In addition, they
may not in every case understand what the various laboratory methods may
involve or why some seemingly “irrelevant” piece of evidence should require such
careful handling. Therefore, the FSD reserves the right to select the appropriate
methods for analysis. It also reserves the right to transfer evidence between the
laboratories of the Divison to best be able to service the request.
This handbook is offered in the belief that increased knowledge leads to
understanding and that understanding leads to excellence. It was written to
provide information regarding the legal and laboratory requirements surrounding
collection and preservation of physical evidence.
This handbook in not intended to be a comprehensive treatment of all of the
factors involved in criminal investigations. Rather, it is a general procedural guide
outlining methods for collecting and preserving physical evidence. Readers
should keep in mind that the information and procedures presented here are
intended to be used as guidelines when encountering other types of evidence not
specifically covered.
Because the laws and legal precedents concerning the collection of physical
evidence are subject to change, it is impossible to give specific up-to-date
information on acceptable procedures. It is, however, of utmost importance that
great care be taken to use only approved methods when obtaining evidence of
any kind. Therefore, it is imperative that during an investigation a close liaison is
maintained between the District Attorney’s Office, the Oregon State Police
Forensic Laboratory, and those persons responsible for the collection of physical
evidence.
1-1