forensicsworld

First photo…“wounds” from left to right…small dagger, hunting knife, large dagger, military style knife. Second photo…the actual knives.

Note the difference between double edged and single edged weapon wounds. Using the dense foam the “wounds” are clearly different. Often the differences are equally clear when examining the skin of a stabbing victim!

At autopsy a thorough examination of stab wounds can reveal evidence of the general type of knife used in a homicide. Examining wounds can also be be very revealing in non-fatal attacks.

Connecting a weapon to a wound is an important part of any forensic investigation!

I’ve posted this one before…did the experiment in my driveway at home! One of my favs!

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USING A LOGHT TABLE TO VIEW FINGERPRINTS ON GLASS:

A light table is a simple but highly effective tool in fingerprint examination, especially when working with transparent surfaces like glass. By illuminating the evidence from beneath, latent fingerprints become easier to detect, photograph, and analyse without excessive handling of the exhibit.

How it works:
When glass is placed on a light table, transmitted light passes through the surface and increases contrast between the fingerprint residue and the background.

Use when viewing…
• Natural latent prints
• Powder-developed fingerprints
• Cyanoacrylate fumed marks
• Smears and ridge detail not visible under normal lighting

Advantages:
-Enhances ridge detail visibility
-Assists photography and documentation
-Reduces glare and reflections
-Helps identify the best angle for examination

Suggestions and Tips:
-Always examine glass under multiple lighting conditions and angles
-Combine using a light table with oblique lighting, forensic light sources, or filters
-Use a clear plastic scale or ruler in your photos

Give a light table a try!

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WHAT IS THE MOST COMMON BLOODSTAIN PATTERN FOUND IN FORENSIC INVESTIGATIONS?

The most common bloodstain pattern encountered in forensic investigations is passive bloodstaining, particularly drip stains.

What are passive bloodstains?

Passive or drip stains are created when blood falls solely under the influence of gravity. They usually occur when a person is bleeding from a wound and blood drips onto a surface without any additional force applied.

Common examples:

* Drip stains – individual drops falling vertically
* Drip trails – a series of drops showing movement
* Pools – blood collecting in one area
* Flows – blood moving due to gravity across a surface

Characteristics of drip stains

* Usually circular if the blood falls straight down onto a smooth surface
* Become elongated when striking at an angle
* May show “spines” or satellite stains on rough surfaces

Passive bloodstains can help forensic investigators determine:

* The position of an injured person
* Movement through a scene
* Direction of travel

Note that there some variations in the labelling of these type of bloodstain patterns. As such without getting into the minutiae of particular terminology, we can all identify and relate to a “drip stain”…the round one! 🙂👍

Like, comment and keep your eyes open for evidence!

USING ARDROX TO PROCESS LATENT FINGERPRINT IMPRESSIONS

Ardrox is a fluorescent dye stain used in forensic science to enhance latent fingerprints after cyanoacrylate (superglue) fuming on non-porous surfaces such as plastic, glass, and metal.

Once applied, the dye adheres to the cyanoacrylate-developed ridge detail and fluoresces under UV or forensic light sources, allowing forensic investigators to visualize and photograph prints with improved contrast.

Commonly used on:
• Plastic packaging
• Fi****ms
• Glass surfaces
• Tape & adhesive materials
• Cartridge cases

In this instance, aluminum foil!

Ardrox can enhance faint prints, reduce background interference and is useful on multicolour backgrounds.

Like, comment and look for fingerprints! 🙂👍

LACERATION vs INCISION WOUNDS

Laceration

Caused by blunt force trauma
Examples: falls, assaults, vehicle collisions

Characteristics:

* Irregular or jagged edges
* Tissue bridging present
* Bruising/abrasion often surrounds the wound

Skin tears from impact.

⸻

Incision

Caused by a sharp-edged object
Examples: knives, scalpels, glass

Characteristics:

* Clean, sharp, well-defined edges
* No tissue bridging
* Usually longer than deep
* Minimal abrasion or bruising at margins

Skin is sharply divided.

⸻

Differentiating wound types helps forensic investigators determine:

* Type of weapon or force used
* Possible sequence of events
* Direction and mechanism of injury
* Whether injuries are accidental, self-inflicted, or assault-related

⸻

In Summary…
Blunt force tears tissue → Laceration
Sharp force cuts tissue → Incision

Like and comment! 🙂👌👍

LACERATION vs INCISION WOUNDS

Laceration

Caused by blunt force trauma
Examples: falls, assaults, vehicle collisions

Characteristics:

* Irregular or jagged edges
* Tissue bridging present
* Bruising/abrasion often surrounds the wound

Skin tears from impact.

⸻

Incision

Caused by a sharp-edged object
Examples: knives, scalpels, glass

Characteristics:

* Clean, sharp, well-defined edges
* No tissue bridging
* Usually longer than deep
* Minimal abrasion or bruising at margins

Skin is sharply divided.

⸻

Differentiating wound types helps forensic investigators determine:

* Type of weapon or force used
* Possible sequence of events
* Direction and mechanism of injury
* Whether injuries are accidental, self-inflicted, or assault-related

⸻

In Summary…
Blunt force tears tissue → Laceration
Sharp force cuts tissue → Incision

Like and comment! 🙂👌👍

LACERATION vs INCISION WOUNDS

Laceration

Caused by blunt force trauma
Examples: falls, assaults, vehicle collisions

Characteristics:

* Irregular or jagged edges
* Tissue bridging present
* Bruising/abrasion often surrounds the wound

Skin tears from impact.

⸻

Incision

Caused by a sharp-edged object
Examples: knives, scalpels, glass

Characteristics:

* Clean, sharp, well-defined edges
* No tissue bridging
* Usually longer than deep
* Minimal abrasion or bruising at margins

Skin is sharply divided.

⸻

Differentiating wound types helps forensic investigators determine:

* Type of weapon or force used
* Possible sequence of events
* Direction and mechanism of injury
* Whether injuries are accidental, self-inflicted, or assault-related

⸻

In Summary…
Blunt force tears tissue → Laceration
Sharp force cuts tissue → Incision

Like and comment! 🙂👌👍

LACERATION vs INCISION WOUNDS

Laceration

Caused by blunt force trauma
Examples: falls, assaults, vehicle collisions

Characteristics:

* Irregular or jagged edges
* Tissue bridging present
* Bruising/abrasion often surrounds the wound

Skin tears from impact.

⸻

Incision

Caused by a sharp-edged object
Examples: knives, scalpels, glass

Characteristics:

* Clean, sharp, well-defined edges
* No tissue bridging
* Usually longer than deep
* Minimal abrasion or bruising at margins

Skin is sharply divided.

⸻

Differentiating wound types helps forensic investigators determine:

* Type of weapon or force used
* Possible sequence of events
* Direction and mechanism of injury
* Whether injuries are accidental, self-inflicted, or assault-related

⸻

In Summary…
Blunt force tears tissue → Laceration
Sharp force cuts tissue → Incision

Like and comment! 🙂👌👍

What happens to a skull when it is exposed to the elements?

Weathering Begins Immediately.
Once exposed outdoors, a skull starts changing due to sun, rain, wind, temperature shifts, and biological activity.

Stage 1: Fresh Exposure

* Tissue begins drying and decomposing
* Insects and scavengers accelerate breakdown
* Moisture and heat speed decomposition

Stage 2: Sun & Temperature Damage

* UV light bleaches the bone surface
* Repeated heating and cooling causes cracking
* Bone may become brittle over time

Stage 3: Moisture & Soil Effects

* Rain and humidity encourage fungal and bacterial growth
* Soil acidity can erode and weaken bone
* Mineral staining may alter coloration

Stage 4: Animal Activity

* Rodents gnaw bone for calcium
* Carnivores may scatter or fracture remains
* Teeth marks can mimic trauma if not properly analyzed

Long-Term Exposure

* Outer layers begin flaking and peeling
* Cracks deepen into structural fractures
* Eventually, the skull may fragment and return to the environment

It takes several months to a year for a skull to appear like this one. The other side of the skull looked significantly different…another post!

This skull was not moved or overly affected by animal activity!

The appearance of a skull, or any bone, can help a forensic investigator estimate:

Postmortem interval
Environmental exposure history
Whether damage occurred before or after death

Finding a skull or any bone is a memorable event!

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What Is That?

In the bloat stage of decomposition, it’s not uncommon to observe air bubbles or frothy fluid emerging from the nose, mouth or even the eyes of a deceased person. While this can appear alarming, it is a natural result of postmortem changes inside the body.

During decomposition, bacteria inside the body begin breaking down tissues and organs. This process produces gases such as:
• Methane
• Hydrogen sulfide
• Carbon dioxide

As pressure builds within the chest and abdomen, these gases seek escape routes…nose, mouth, eyes.

When mixed with decompositional fluids or moisture in the airways, the escaping gas can create visible bubbling or frothing.

Postmortem bubbling or frothing caused by decomposition should not automatically be mistaken for signs of drowning, overdose, or pulmonary edema. Scene context, autopsy findings, and the overall condition of the body are critical when interpreting these observations.

Understanding normal decomposition processes helps forensic investigators distinguish expected postmortem changes from potential evidence of trauma or foul play.

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