Policy Text
San Francisco Police Department 6.02
GENERAL ORDER Rev. 06/ 14/23
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Physical Evidence and Scene Preservation
6.02.01 PURPOSE
The purpose of this order is to describe the policies and procedures for determining what
constitutes a crime scene or major incident scene and recognizing, preserving , and booking
physical evidence.
6.02.02 DEFINITIONS
A. Crime Scene or Major Incident Scene – A crime scene or major incident scene is a location at which there has been an event involving potential or actual injury, death, or
property damage requiring an exceptional emergency response. This includes non-
criminal natural disasters (floods, earthquakes, major fires, etc.) and human -caused
emergencies (major traffic collisions, industrial accidents, plane crash, riot, terrorist acts,
hostage situations, high profile events which may cause public unrest etc.), which require
extensive response and commitment of resources to control or resolve. An incident scene where a Critical Incident has been declared is a Major Incident crime scene (See DGO
8.01, Major and C ritical Incident Evaluation and Notification) and includes not only the
area where the criminal or non -criminal act occurred, but also approaches and exits that
the suspect(s) may have used, i .e., point of entry and exit. Not all evidence is visible.
B. Physical Evidence – Physical evidence is anything that has been used, left, removed,
altered, or contaminated during the commission of a crime or incident by the victim(s) or suspect(s) or involved parties.
C. Buccal swabs – swabs taken from the inside of a person’s mouth for use as a DNA
reference sample.
D. Contact swabs – swabs taken from an individual (hands/fingers/fingernails or other body
parts) for potential evidence.
E. Chain of Custody – Chain of Custody refers to the documentation of who had possession of the evidence, from the time of collection to the time of analysis and
beyond.
F. Critical Evidence – Evidence that merits careful consideration and protection due to its potential relevance, or fragility or sensitivity to contamination . These items may include
deceased bodies, biological material, footprints, fingerprints, tire tracks, fibers, and other
trace evidence.
DGO 6.02
Rev. 06/14/23
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G. Digital Evidence – Digital evidence includes all media capable of storing data including
mobile devices, computers, game consoles, hard/solid state drives, drones, optical media,
and flash media.
H. Questioned Documents – Questioned documents are checks, credit card receipts, threat
and extortion letters, robbery notes, business records, etc.
6.02.03 POLICY
A. Preventing Contamination of the Crime S cene and Major I ncident Scene – It is the
policy of the San Francisco Police Department ( SFPD ) to ensure that crime scenes are
preserved for investigation and for the collection of uncontaminated and undisturbed
evidence. Physical evidence shall be collected using methods that maintain, to the
furthest extent possible, the integrity of the piece of evidence for further analysis. SFPD
policy follows the guidance of national accrediting agencies and organizations, as well as
that of experts in the field. The careful and proper preservation, collection and booking,
and the documentation of chain of custody for all evidence collected, is critical to
investigative efforts and to later court cases. (See DGO 8.11, Investigation of Officer
Involved Shootings and Discharges )
B. Chain of Custody – The legal requirements for evidence that will be introduced into
court may be more stringent than the requirements for evidence that is used solely to
justify an arrest. Officers shall, at all times, maintain and document the chain of custody.
6.02.0 4 PROCEDURES
PRESERVING , COLLECTING , AND TRANSPORTING PHYSICAL EVIDENCE
AT CRIME SCENES / MAJOR INCIDENT SCENES
A. Recognizing a Crime Scene or Major Incident Scene – Members shall contact the
Crime Scene Investigations (CSI) or specialized investigative unit if any questions arise as to the scope of an incident scene and/or physical evidence. It is the responsibility of
first responding officers at the scene to notify the Department Operations Center (DOC) ,
when applicable, or CSI , if there is potential for recovering physical evidence or a need
for specialized documentation, handling, and processing. If CSI is responding, members shall take steps to ensure that the potential evidence is protected.
B. Roles and Responsibilities of Investigative Units
1. Specialized Investigative Units – When required, specialized investigative units
shall respond to conduct investigations into criminal and some non- criminal incidents
as outlined by current policy. If an Investigator is responding to a scene, members shall make every effort to preserve the scene and evidence within.
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2. Crime Scene Investigations Unit – CSI is a specialized unit composed of Crime
Scene Investigators who have extensive forensic training. CSI personnel are on- duty
seven days a week from 0600- 2400. After hours, for scenes that meet CSI call out
criteria, on- call CSI personnel will be notified through DOC and will respond to
crime scenes and major incident scenes which require immediate, specialized
documentation or processing.
C. Identifying and Preserving Crime Scenes and Major Incident Scenes – It is the
responsibility of responding officers to isolate and protect crime scenes