April Report, Part 1: CSI: Minneapolis!

The meeting was called to order at 6:30 with 13 attenders.

Shay Sward and Emily Bakken presented “Minneapolis Police Department — Forensics Division”


The Division includes Lab Administrators, Forensic scientists and technicians, and support staff.   Some members are civilians and others are sworn officers.  

Qualifications for becoming a Forensic Scientist 1 are:

Bachelor’s degree in a qualified science or in criminal justice,

2-year training program focused on crime scene processing and fingerprint analysis   [EQ: people in the field now refer to this as “friction ridge analysis and comparison] 

3-part examination including a written text, latent print analysis and comparison exam, and evaluation of 10 crime scene photographs.


Video forensics is the scientific examination, comparison, and evaluation of video,  for use in legal proceedings.  The goals are image and audio analysis for identification of suspects (by physical comparisons and clothing comparisons) and vehicle descriptions.   

Videos are obtained from:

  • Businesses
  • Private residences
  • Milestone cameras [EQ: these are City cameras, fixed and portable.  A look at the company shows they provide broad service so Minneapolis may have more Milestone products in use than the street cameras: https://www.milestonesys.com/]
  • SafeZone cameras.   [EQ:  2-PAC was introduced to the Safe Zone concept by former CM Steve Fletcher.   The program is now a wholly owned subsidiary of the Downtown Improvement District; it now encompasses 120 blocks.  FFI:  See https://courtwatch2pac.com/2019/03/20/march-2-pac-report-part-1/   and Google “Minneapolis Safe Zone” and  was reported   throughout the city.] 

Computer forensics is the examination of digital media to provide factual data in an investigation, which may or may not provide evidence of illegal activity.  This may include examination of cell phones, tablets, hard drives, flash media optical discs.

Firearms and toolmark examination

  • Firearms may be examined and compared to determine firearm proximity from the target and function testing.  Obliterated serial numbers can be restored.
  • Discharged cartridge casings are entered into the Integrated Ballistic Identification System or IBIS.   The marks and data are held for comparison with other casings in the database, and may become part of ballistic evidence in a case.

Field operations

Forensic garage: Here vehicles involved in criminal activity will be examined to find latent prints, DNA, hidden compartments, potential  mechanical problems, VIN (Vehicle Identification Number) changes, bullet trajectory.
MAFIN/AFIS  [EQ: Midwest Automated Fingerprint Identification-Network/Automated Fingerprint Identification System]:

This is a computerized network that compares a series of plotted points on a fingerprint with prints in a database of known  prints.

  • Latent entry: a print is searched against a database of known prints.   Minutiae points are identified and plotted.   These points and other identification marks will be discussed later.  
  • Reverse searches are when a suspect’s prints are compared with stored latent prints. 

Field operations:  the 24/7 response to crime scenes including

  • Crime scene documentation:  Includes creating photographs, video, sketches of the scene.
  • Crime scene processing:  Gathering physical evidence, latent prints, footwear & tire track impressions, DNA, Bloodstain pattern documentation
  • Evidence collection

Examination and comparison of latent prints. 

Assist the medical examiner’s office in making identifications.

Crime scenes: The office responds to Robberies, Burglaries, Criminal sexual conduct, Deceased on arrival (DOA), Search warrants, Shootings, Homicides, Officer-involved shootings.

Crime scenes: 

What do we know so far?

Statements from officers, witnesses & victims.

Scene walkthrough:

Initial search for items of interest

Evidence labeled with evidence markers

Search Points of entry and exit, any disturbed areas

Begin documentation.   [Photos shown on the presentation video show a set of 3 pictures locating the big scene of a street storm drain with numbered casings,  a mid-distance photo of a casing with a number tag next to the storm sewer grill, and a close up showing the tag and the casing.] 

Additional Documentation

Video:  Used for homicides, officer-involved shootings, and critical incidents

Walk-through of the scene from beginning to the end

Allows  viewers to get a sense of what the scene looked and sounded like at the time of our processing

Done as close to the incident time as possible.

Sketch:  Used for homicides, officer-involved shootings, and critical incidents

Used to place evidence and get spatial representation in the context of the scene

Rough sketch done at the scene using approximate measurements

Measurements taken to fixed landmarks

Final sketch done using GPS satellite images or drawn with a computer program.

Scene processing:

Evidence processing performed by Field Operations:

Latent impression

Biological evidence collection: DNA, blood, semen, saliva

Footwear & tire track collection

Firearms collection

Trace evidence collection (including hairs and fibers), bloodstain pattern documentation.

Additional search tools can be utilized following the visual search:

Metal detector,

ALS [alternate light sources]  Using ALS (generally ultraviolet light) investigators can locate identify fluids like semen, urine, and saliva which have natural fluorescent properties.


The skin on the inside surface of your fingers has ridges and furrows that  help you grip items.   This is called friction ridge skin.

A “fingerprint” is the tracing of this pattern of friction ridges and furrows left when oil is deposited on an item you grip.

Two facts about fingerprints make them the ideal for identifying people:

No two people (including identical twins) have identical prints, and

Friction ridge skin is persistent throughout life.  

Print Processing:   Fingerprints may offer any of three types of impression.   They may be latent (only visible after processing), or “patent” visible without processing, or “plastic”, visible on a surface that retained a print impressed on it.  [Pictures shown on video.]

Latent Print Processing:  processing to enhance detail that can’t normally be seen.  Adds contrast and preserves prints.   The processing technique is determined by the surface type and transfer medium.  

Latent print processing techniques: 

Powder dusting: Powder particles adhere to  the moisture/solids of the print

Superglue fuming:  Fumes from heated super glue adhere to objects in the heat chamber

Chemicals:  different surfaces are processed with specific chemicals.  

Biggest misconception is that fingerprints WILL be present if the item was handled by a suspect.   This isn’t true; contributing factors include:  

           The composition of the item being handled.

           The person handling the item — the natural oils left behind by a person are analyzed for ID.

The environment may preserve or corrupt fingerprints

[EQ: Pictures of treated fingerprints are presented on the YouTube video.] 

ACE-V methodology:  Analysis, Comparison, Evaluation, Verification

This is the checklist checklist technicians keep in mind when doing their analysis for reports.

Fingerprint examination involves identifying the increasingly tiny differences that make each fingerprint unique.

Level 1: Pattern types – Three  descriptors based on the presence or absence of “deltas”, described as the “divergence of two ridges”.   It is named for the Greek letter, Delta, symbolized by a triangle.   [EQ:  Think of the top of the triangle where the two sides spread apart to meet the base.]   

A finger print may have arches (no delta = 5% of the population), loops (one delta = 65%) or whorls (2 deltas = 30%)

Level 2: Minutia points  – details found within the fingerprint patterns including ridge endings (the ridge stops), shorts (tiny ridge segment) and bifurcation (a very narrow delta-like form that extends as parallel lines, in contrast with deltas which are not parallel lines)

Level 3: Creases, pores, irregular line shapes, incipient ridges, warts, scars.    It’s apparent at this level, why everyone’s fingerprint is theirs, alone. 

The Bureau of Criminal Apprehension Lab is a  collection of lab spaces and specialized appliances including chemical hoods, heat chambers, and more. [EQ: pictures in the video.]

In addition to Fingerprint Analysis, Forensics involves

Toxicology, the study of toxins and drugs

Anthropology: the study of skeletal remains

Pathology: determining the cause of death

Entomology: study of insects

Odontology: dental evidence

Serology: study of body fluids

Bloodstain pattern analysis

Document examination: study of questioned documents

Accounting:  examination of financial records to uncover financial crimes.

Case Study — homicide stabbing

Photos of a crime scene beginning with an exterior photo of a house, point of entry (smashed kitchen window), several photos show blood spatters and evidence of struggle in kitchen and living room, non identifying photos of the victim as she was found.   [EQ: see these on the YouTube video]

The photos show what kinds of processing the lab could do:  latent prints, blood spatter, DNA,

The team actually processed the following items for latent prints:  storm door, porch door, main door, kitchen drawer, window and table, microwave & stand, kitchen phone, hallway walls,      Latent prints were found on a cabinet door, a phone,  and a hallway wall. Latent prints were found on the front door.   Blood-like traces were found on a plastic shopping bag, a knife, credit cards, a newspaper. 

The outcome of this case:  A latent print from the hallway was entered into the Automated Fingerprint Identification System [MAFIN/AFIS  referenced above] and they got a match.   Additional latent prints from the window and the phone match the same suspect.   At the same time, a father turned his son in for having items that belonged to the victim.  Based on the fingerprints collected at the scene, this person was positively identified as the suspect. 

Thanks for solid work go to the MPD Forensics Division!


QQ: Do you coordinate with other agencies>

AA:  We only do fingerprints in our lab.  Anything we swab, we send on to others.   We have a good connection with the Bureau of Criminal Apprehension.    We work with the FBI often, also.

QQ:  Printed guns:  do they leave the same kinds of marks on a casing as a regular gun?

AA:  They may, but they can only be used once, so you wouldn’t get a hit in the database.  You COULD get a fingerprint, though.

QQ: Can a fingerprint suggest the age of a person?

AA: The size of a print might — a small print might indicate a juvenile.   A print can age though.  With chemical enhancement we might be able to bring something up.

QQ: What surfaces yield the best prints?

AA: Grocery bags are  good sources if we put them in a superglue chamber.   In general, any non-porous surface is  good like glass or tile.  We can get prints from porous surfaces like wood or paper though.

QQ: Can you change your own fingerprints?

AA:  People try, but don’t succeed.  At first their attempts give them a really distinctive print, and eventually the original pattern of ridges re-emerges. 

QQ: How do you take shoe prints?

AA:  It’s not that different.   We start with photos and can go on to take a cast.

QQ: How many personnel are assigned to a scene?

AA: We have three shifts a day, so 5 or 6 people-in a 24-hour period.   Each shift must have 2 on duty, to respond at 2 on a call.

Bakken wanted to expand to the question of staffing.  
While most staff either started out as officers or follow the path of Bachelor’s-Degree-to-training-program-to-test, other staff members come from a variety of backgrounds.   The forensic artist, for example, took a very different path to Forensics.

EQ:  I found two relevant websites on this meeting’s topic:   Inside MPD titled “A Look Into the MPD Crime Lab” was produced by the MPD for National Forensic Science Week 2020  The  Facebook video is at https://www.facebook.com/watch/?v=1501531263391243 



Emilie Quast, Board member

MPD Second Precinct Advisory Council (2-PAC)



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