MPD 2-PAC 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”
WHAT IS THE FORENSICS DIVISION?
The Division includes Lab Administrators, Forensic scientists and technicians, and support staff. Some members are civilians and others are sworn officers.
FORENSICS DIVISION SECTIONS:
Video forensics is the scientific examination, comparison, and evaluation of video, for use in legal proceedings. Videos are obtained from: Businesses, Private residences Milestone cameras [EQ: City cameras, fixed and portable.] SafeZone cameras.
Computer forensics is the examination of digital media to provide factual data in an investigation …. This may include examination of cell phones, tablets, hard drives, flash media optical discs.
Firearms and toolmark examination – Firearms may be examined to determine distance fired and more. Serial numbers can be restored. Casings marks are entered into the Integrated Ballistic Identification System or IBIS, and are held to compare with other casings in the database
Forensic garage: Vehicles are checked for 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 database used to identify new prints with prints already in the database.
Field operations: the 24/7 response for crime scene documentation: Includes photographs, videos, and sketches of the scene. Scene processing is gathering physical evidence, latent prints, footwear & tire track impressions, DNA, Bloodstain pattern.
Crime scenes: The office responds to Robberies, Burglaries, Criminal sexual conduct, Deceased on arrival (DOA), Search warrants, Shootings, Homicides, Officer-involved shootings.
Gather statements from officers, witnesses & victims. Walk through looking for evidence which is labeled with markers and located on the sketch. Begin documentation.
Video is used for homicides, officer-involved shootings, and critical incidents. A walk-through of the scene allows viewers to get a sense of what the scene looked and sounded like when the lab got there. Processing is 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 to mark evidence location.
Scene processing performed by Field Operations includes collection of DNA, blood, semen, saliva, footwear & tire track, bloodstain pattern documentation.
Additional search tools can be utilized following the visual search:
ALS [alternate light sources] Using ALS (generally ultraviolet light) investigators can locate identify fluids like semen, urine, and saliva which have natural fluorescent properties.
FINGERPRINTS: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 natural skin 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
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.
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.
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: Plastic 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)