The patrol officer is responsible for the preliminary investigation of all crimes and incidents which are assigned or reported to her/him or which s/he discovers. The scope of the preliminary field investigation by a patrol officer may constitute the entire investigation. Patrol officers conducting preliminary investigations will follow-up the reported offense as far as possible. The follow-up will include, but is not limited to, canvassing the vicinity of the scene for witnesses and a search for physical evidence.
Nothing in the above is to be construed as prohibiting any sworn officer from initiating a preliminary investigation should circumstances dictate that the action is appropriate.
Preliminary Field Investigation Procedures:
These are general investigative procedures to be followed as they apply.
Scope of Preliminary Investigation:
- Begins upon discovery or report of crime. Speed of initiation of investigative process is often crucial.
- Ends when everything possible has been done.
Responsibility for Preliminary Investigation:
1. Operations has responsibility for:
A. Immediate response to crime.
B. Acting to apprehend offender.
C. Preservation of life and property.
2. Manner of discharge of responsibility dependent upon type of offense and other factors. Techniques and procedures impossible to predict on a case-to-case basis.
3. In general, the preliminary investigation may include, but are not limited to the following:
A. Proceed to the scene promptly and safely.
B. Render assistance to any injured.
C. Determine if a crime has been committed.
D. Affect an arrest of suspect(s) if possible.
E. Protect the crime scene as completely as possible.
F. Notify your supervisor and/or investigative unit, if necessary.
G. Note all conditions, events and remarks made by persons present.
H. Interview complainant and witnesses.
I. Protect or arrange for protection of evidence.
J. Inquire with businesses and citizens for video evidence.
K. Collect and preserve evidence and/or arrange for collection and preservation by forensic services personnel.
L. Locate and identify witnesses (neighborhood canvas).
M. Report the incident accurately and fully according to the manual.
N. Interrogate suspect(s).
O. Submit all reports to the on-duty supervisor. All reports must be written, submitted, and accepted before the officer s shift is over.
P. Contact the watch commander when available prior to booking suspects and/or in cases of serious offenses. In the watch commander s absence, the unit or officer s immediate supervisor will be notified.
Duties of First Officer(s) at Scene:
1. Care of injured.
A. Saving life is our paramount duty.
2. Determine if crime has been committed.
3. Arrest perpetrator if still at scene.
A. Pursue if apprehension likely.
B. Identify or describe as quickly as possible and alert other units through communications systems.
C. Separate offenders, if possible.
4. Separate witnesses, if possible, to insure personal independent recollection.
5. Protect crime scene.
A. Insofar as possible, isolate crime scene.
B. Keep out all unauthorized persons, including police officers not actually engaged in investigation.
6. Arrange for collection of physical evidence.
7. Locate, identify, and interview witnesses and interrogate suspects.
A. Obtain names, addresses, and telephone numbers of witnesses whether they have left the scene or not.
8. Important conditions/events should be recorded.
A. Time of arrival, notification or discovery.
B. Weather conditions.
C. When discovered by whom, etc.
D. Approximate time of commission of crime.
9. Reports.
A. Accurate and complete.
B. Patrol officer prepares the state crash report original offense report and supplementary reports as required.
C. Investigators write supplementary reports.
D. All arrest reports and response to resistance and aggression reports must be written, submitted, and accepted to the on-duty supervisor before the officer s shift is over.
10. Serious crimes.
A. Notify the watch commander as soon as possible of nature of crime.
B. If the watch commander is not working, notify the patrol sergeant who will notify the district commander and the on-call assistant chief.
Duties of Supervisors (On-Duty)
- Ensure all reports are submitted correctly prior to the end of shift. If officers are still writing an arrest report, the supervisor shall notify the next on-duty sergeant of the situation to ensure the case reports are completed.
- Take immediate action to notify the chain of command and/or internal affairs if the supervisor is told or becomes aware of a violation of department policies and procedures.
- Respond to all response to resistance and aggression incidents in the supervisor s district.
- Approve all arrests before officers detain individuals at the LEC.
Search for Physical Evidence:
The following guides are useful in situations where evidence collection will be handled by persons other than Forensic Services personnel.
1. Record:
A. Description of each piece of evidence found.
B. Date, time, and location found.
C. How and where marked.
D. Identify all persons handling evidence to show chain of possession.
E. Disposition of evidence.
2. Search of crime scene:
A. Survey and plan manner of search.
B. Sketch or arrange for photographs of crime scene.
C. Search for marks, stains, and general conditions of significance.
D. Search for traces of material important to inferring injury, weapons, and tools used.
E. Search for signs of forcible entry.
F. Do not mix evidence. Separate items of evidence and package individually.
G. Measure where necessary to determine positions of evidence items or internal building construction.
H. Photographs will be taken of all serious crime scenes. When photographs are not taken, an explanation as to why the photographs were not taken will be included in the original or supplementary reports.
I. When physical evidence is not recovered at the scene of a serious crime, an explanation as to why physical evidence was not collected will be included in the original or supplementary report.
J. Whenever available, materials and substances from a known source will be collected for submission to the property room. The identification and comparison of evidence collected with samples from a known source carries a significant degree of value. The location from which a known source sample is obtained must be documented.
Delineation of Authority:
- The primary squad dispatched to a crime scene is responsible for that scene. That officer will write the original incident report and process the scene for latent finger prints and physical evidence. If in the opinion of the primary officer a supervisor is required at the scene, the primary officer may request a supervisor.
- Upon arrival at the scene, a supervisor may assume responsibility of the scene directing the primary officer to continue the processing. The supervisor may also request the assistance of a crime scene response officer or, with approval of the watch commander or district commander, the services of the forensic services unit to process the scene.
- The supervisor may also request an investigator to the scene. Upon her/his arrival, the investigator will be responsible for supervising the processing of the scene.
- If the forensic services unit is summoned to the scene by the watch commander or district commander, the responsibility for processing the scene rests with forensic services personnel.
- In all cases, officers at the scene may be directed to assist with the processing.
Revised June 7, 2016