Postmortem Injuries from Animals

Terri ArmentaForensic Training Unlimited

terriarmenta@forensictrainingunlimited.com

Course Objectives

• Learn how different types of animal bite patterns are determined via pattern activity

• Be aware of the common characteristics seen in postmortem injury patterns

• Be familiar with the common body areas artifacts may be found on decedents

Characteristics

• Wound margins can be irregular• Areas can be circular in nature• Tooth marks present• Claw marks +/- present• Can be found clothed/unclothed decedents• Homeless, outdoors (common aspects)• Low socioeconomic environments

Common Areas on Decedents

• Exposed and unprotected areas of body• Eyelids• Moist Areas of body– Nose– Mouth

• Back of hands• Loss of tissue • Blood evidence +/- may be present

Evidence Associated

• Bite patterns• Bite/tooth marks on decedent bones?• History of decedent• Feces found?• Area decedent found? Where? When? • Decedent bones crushed? – Crush/puncture bones via canine (teeth)

Type of Animals

• Non-Carnivores (scrape surface pattern)– Rodents (mice, rats)– Porcupines– Opossums– Raccoons

• Carnivores (chewing pattern)– Dogs– Coyotes

Disclaimer

Some may find these images disturbing. This presentation is for educational purposes and is meant to be viewed as such.

The case studies presented during this course represent artifacts found in cases such as these. Artifacts may and do appear differently; depending on the case and circumstance.

Case Characteristics

• Case Findings– Dressed in PJs– Nose (large defect)– Mattress revealed

rodent nests– Rodent feces found

• Autopsy Findings– Cartilage exposed– Wound edges were

irregular and serrated– Large adenoma on

thyroid gland– Aspiration of vomit,

coronary artery disease– Tox=negative– Death: respiratory

insufficiency

Case Study: Rats

• 41 y/o male; homeless, history of alcohol• Found fully dressed on mattress• Observed many rats in environment• No external injuries

Autopsy Findings

• Pneumonia• Chronic tracheobronchitis• Pulmonary emphysema• Hemorrhagic gastritis (bleeding in stomach)• Fatty Liver• Tox=alcohol in blood and urine• Death=respiratory insufficiency combined

with gastric bleeding

What Happened?

• Before and after photos reveal differences of hands

• Before photos– No defects noted– Injury not found on body

• After photos– Defects noted– Concluded injuries 45-60 minutes after initial

photos (before coroner arrived)

Autopsy Findings

• Circular soft tissue defect• Finely scalloped and serrated wound on back

of hand• Hand muscles exposed

Case Study 3: Mice

• 61 y/o male• Wearing only t-shirt and socks• Mouse feces found near head• Scene findings– Untidy– Number of empty alcohol bottles– No signs of struggle

Autopsy Findings

• Hand– Serrated wound patterns– Many lacerations

• Head– Defect found on left side of face– Nose, orbit, and cheek bone exposed

• Death=bronchopneumonia • Tox=negative

Case 4: Mice

• 44 y/o male; found in the park

• Temps below zero• Fully dressed• Death Scene– Defect on right side of

face; right ear missing

Autopsy Findings

• Defect on right forehead, face• Wounds serrated with irregular edges (gnaw

marks)• Multiple hollow defects found on back of body

(previous image)• Tox=alcohol in blood and urine• Death=pulmonary edema, necrosis of the

kidneys; hypothermia in combination with alcohol intoxication

Case 7: rats and mice

• 58 y/o male• Found in apartment• Serrated wound

margins• Scene findings– Apartment was in

disorder– Garbage in apartment– Rat and mouse feces

found in all rooms

• Autopsy– Defects found around

both upper/lower eyelids

– Bleeding gastic ulcer– Blood in stomach, small

bowel– Tox=negative– Death=atherosclerosis

and coronary artery disease

Conclusions

• Each death scene is unique• Look at all aspects of evidence– No blood present?– Feces present?

• Cases need to be investigated with an open mind and don’t allow assumptions “rule” an investigation– Gnaw marks could be observed as a result of a

sharp blade

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