latent print deposition & recovery types of latent fingerprints the most common form of transfer...

LATENT PRINT DEPOSITION & RECOVERYTypes of Latent Fingerprints

The most common form of transfer evidence that technicians seek at a crime scene is latent fingerprints:

1. Latent fingerprint evidence is hidden, barely visible and requires development with powders or chemicals.

2. Patent fingerprint evidence is visible and does not require development.

3. Plastic fingerprint evidence is visible as a three-dimensional impression in a soft surface like putty.

Latent Print Developed with Powder.

Photographed Patent Bloody Palm Print.

Plastic PrintImpressed in Clay.SLIDE 1

CLASSROOM FORENSICSTM & Scientific InquiryLatent Print Deposition and Recovery Lab© 2006 FORENSIC PRESS All Rights Reserved

LATENT PRINT DEPOSITION & RECOVERYHomicide: Case History

Bloody Patent Palm Print on Dollar Bill.

SLIDE 2CLASSROOM FORENSICSTM & Scientific InquiryLatent Print Deposition and Recovery Lab© 2006 FORENSIC PRESS All Rights Reserved

The most common method to develop transfer evidencelike fingerprints is to use fingerprint powders:

1. Conventional fingerprint powder is applied with a brush, is very fine and becomes airborne when applied to the evidence.

2. Magnetic fingerprint powder is applied with a magnetic applicator, is heavy and does not become airborne when applied to the evidence

You will learn how to use a magnetic powder system to develop transfer evidence in this inquiry.

LATENT PRINT DEPOSITION & RECOVERYTypes of Fingeprint Powders

Photo Courtesy ofSIRCHIE® Finger Print Labs., Inc.


LATENT PRINT DEPOSITION & RECOVERYAdvantages of Magnetic Powder

1. Magnetic powder can be controlled with two

commonly-known forces: magnetism and gravity.

2. Magnetic powder works effectively on a number of

different evidence surfaces.

3. Magnetic powder can be used, then put back into

the jar, so it can be used again.

4. Magnetic powder does not have to be messy.

Latent Print Developed with Magnetic Powder.


Your inquiry includes an array of slick-surface cards that will perform as a proxy, or substitute, for an actual evidence surface.

The evidence proxy cards feature surface qualities like you would find on glass, painted wood and plastic and countertops.

To learn basic methods of transfer evidence processing, you will purposely deposit transfer evidence onto proxy cards, then develop it.

After the labs, you will have a collection of latent prints to examine and discuss.

LATENT PRINT DEPOSITION & RECOVERYUsing an Evidence Surface Proxy

Ear Print Developed with Magnetic Powder.


Objects Often Processed With Magnetic Powder:

1. Glass: drinking glasses, eyeglasses and rear view mirrors2. Plastic: bags and wrapping material3. Fiberglass: car and boat surfaces4. Painted and stained wood: windowsills, doors and handles5. Paper: slick surfaced paper, catalog sheets, flyers and magazines

Objects Sometimes Processed With Magnetic Powder:

1. Metals: aluminum, steel, handguns, knives2. Paper: regular paper with porous surfaces3. Skin: arms and legs

LATENT PRINT DEPOSITION & RECOVERYEvidence Surfaces and Items Processed


LATENT PRINT DEPOSITION & RECOVERYThe Magnetic Powder Applicator

The Magnetic Applicator Has Two Separate Parts:

1. A rod with a magnet on one end (blue part).

2. A clear plastic housing.

How The Applicator Functions:

The rod slides up and down inside the plastic housing.

You slide the rod down to position the magnet inside the tip

of the housing.

When the tip is down, powder will attract to it.

When you pull it up, the powder will fall off.


LATENT PRINT DEPOSITION & RECOVERYEngaging Powder on the Applicator Tip

To engage the powder onto the applicator, you lower the tip near the powder.

Magnetism will cause the powder to jump up onto the tip, making a bristle formation or powder plume.


LATENT PRINT DEPOSITION & RECOVERYThe Powder Plume

The powder plume is formed from the combination of magnetic attraction and gravity.

The plume consists of elongated powder rays that will dangle over the evidence surface.

You will hold the applicator in this position as you carefully sweep it just above the evidence surface.


LATENT PRINT DEPOSITION & RECOVERYCloser Inspection: Controlling the Powder Plume

1. Slide the applicator down, lowering the tip to the bottom of the housing.

2. Lower the tip of the applicator into the powder.

3. Watch the powder jump up onto the tip.

4. Slightly flick the side of the applicator so a small amount of powder drops off.

5. Holding the applicator in a downward position, practice moving it around slowly with no sudden stops or jerks.

Powder Plume


LATENT PRINT DEPOSITION & RECOVERYMagnetic Applicator Procedures

You must learn how the applicator functions and how to control the powder before you can process evidence.

You must learn how to disengage the powder by lifting the rod up and down quickly. Most of the powder will fall down on the workspace.

Excess powder can be removed from the applicator by quickly lifting the rod up and down until it falls off.

Powder Released Over Palm Print.


You must constantly inspect the powder plume to be sure that it has the proper bristle formation.

When necessary, you will have to replenish the powder by picking up the powder that fell off.

This plume maintenance is extremely important.

LATENT PRINT DEPOSITION & RECOVERYPowder Plume Maintenance


Reengaging Powder Onto The Applicator.

LATENT PRINT DEPOSITION & RECOVERYDepositing Latent Prints on the Placemat


LATENT PRINT DEPOSITION & RECOVERYHow to Prepare Your Fingers and Palm for a Deposition

1. Rub hands together to make them warm.

2. Touch fingers to forehead and nose. That usually is an area with skin oils.

3. Touch fingers to back of neck. That usually is an area of moisture or perspiration.

4. Rub your hands together slowly to distribute the oil and perspiration.Your fingers and palm now should have a residue that you can deposit.

You now are ready to make a controlled latent print deposition on your placemat.


LATENT PRINT DEPOSITION & RECOVERYDeposition of Latent Finger and Palm Prints

Touching the finger on the placemat is a deposition.

This deposition replicates a suspect touching an evidence surface during the commission of a crime.

Latent print deposition occurs when the moisture, sweat, oils in combination with the warmth from your hand transfers to the receiving surface.

This deposit is invisible. You must develop it with powder!

Fingerprint Deposition

Palm Print DepositionSLIDE 15CLASSROOM FORENSICSTM & Scientific InquiryLatent Print Deposition and Recovery Lab© 2006 FORENSIC PRESS All Rights Reserved

LATENT PRINT DEPOSITION & RECOVERYDeveloping the Latent Prints on the Placemat


LATENT PRINT DEPOSITION & RECOVERYPowder Applicator Mechanics

The invisible latent prints are on the placemat. You have to learn how to operate the magnetic applicator to recover or find them.

Slide the rod down into the engage position and place it over the powder.

The powder will jump up to the tip like in the photograph.

Before applying powder to your deposited latent prints, practice engaging and disengaging the

powder on the applicator.


LATENT PRINT DEPOSITION & RECOVERYApplying Powder to Evidence Surface Proxy

The powder plume is seen being lightly passed over the first finger box.

Do not proceed to the next finger until you have completely developed the first finger deposition.

You will process each box separately, not all together at one time.

Powder Application


LATENT PRINT DEPOSITION & RECOVERYRecognizing a Good Plume and a Bad Plume Formation


Which is a Good Powder Plume Formation?

LATENT PRINT DEPOSITION & RECOVERYProper Applicator Movement Question

Which direction should the applicator pass over the evidence surface?


LATENT PRINT DEPOSITION & RECOVERYProper Applicator Movement Illustrated

Pass The Applicator in The Direction of the Ridge Flow. SLIDE 21CLASSROOM FORENSICSTM & Scientific InquiryLatent Print Deposition and Recovery Lab© 2006 FORENSIC PRESS All Rights Reserved

LATENT PRINT DEPOSITION & RECOVERYComparing an Inked Fingerprint Exemplar to Recovered Latent Prints

Inked Fingerprint Exemplar Developed Latent PrintsA. B.


LATENT PRINT DEPOSITION & RECOVERYTape Placement Over Recovered Latent Prints

Hold Tape By Tab Handle and Lower onto Card Surface.

Wrap Tape Around the Back of the Card and Press Out Air Bubbles.



2. Touch fingers to forehead and nose.

3. Touch fingers to back of neck.

4. Rub your hands together slowly to distribute the

oil and perspiration.

5. Rub your fingers and palm against one of the

heels of your shoes.

6. Step on the evidence proxy card with the heel

of this shoe.

LATENT PRINT DEPOSITION & RECOVERYShoe Heel Deposition

Depositing The Latent Heel Print.


Processing the Latent Heel Print.

LATENT PRINT DEPOSITION & RECOVERYShoe Heel Print Recovery

Use the same powder application skills you learned in the finger and palm print exercise to develop the latent heel impression.

Place a section of tape over the card to secure it.


LATENT PRINT DEPOSITION & RECOVERYEar Print Deposition


2. Touch fingers to forehead and nose.

3. Touch fingers to back of neck.

4. Rub your hands together slowly to distribute

the oil and perspiration.

5. Touch your fingers and palm against your ear

lobe to transfer this residue to the ear.

6. Press the ear print card against this ear.


LATENT PRINT DEPOSITION & RECOVERYTape Placement Over Recovered Latent Prints

Use the same powder application skills you learned in the finger, palm and heel print exercise to develop the ear print deposition.

Place a section of tape over the card to secure it.


Locard’s Evidence Exchange Principle

Edmond Locard wrote that ‘when a criminal commits a crime, he comes in contact with an object and an exchange of evidence occurs’.

The goal of the forensic scientist is to examine, process and develop items of evidence that can link to the perpetrator and/or victim of crime. When such evidence is discovered, it can be used in court to convict the guilty person.

LATENT PRINT DEPOSITION & RECOVERYInquiry Review


In your operative latent print deposition and recovery exercises, you learned how to utilize a magnetic powder system. This skill enables you

to develop an invisible latent print and make it visible.

Now that you learned how to use this tool, you will be able to enhance your skills and improve your knowledge of evidence inquiry and forensic science.

LATENT PRINT DEPOSITION & RECOVERYInquiry Review


LATENT PRINT DEPOSITION & RECOVERYClosing Remarks

Latent Print Processing

1. Powder Application Skills2. Observation and Vision3. Motivation4. Dexterity5. Patience6. Thoroughness7. Satisfaction / Disappointment8. Research and Development


latent print deposition & recovery types of latent fingerprints the most common form of transfer...

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