Forensic examiners are sometimes called upon to identify deceased persons by means of their fingerprints. This one-day Recording Friction Ridge Deatils from the Deceased course covers techniques that can be employed in this process, concentrating on cases where the recovery of friction ridge detail can be most difficult. Examples of this include attempting to recover such detail from decomposed, waterlogged, or burnt bodies. Students will take part in exercises designed to reinforce material instructed in the lecture series.
Topics include:
Morphology of Fingerprints – In this introduction the instructor will describe the difference between smooth skin and friction ridge skin. The instructor will give the class a brief explanation about the uniqueness and persistence of friction ridge skin and how after a person becomes deceased the process of decomposition will stop the regeneration of the skin.
Requirements for Recording Friction Ridge Detail– In this section the instructor will show the students examples of properly recorded friction ridge impressions. These examples will show the full pattern area of fingers and palms being recorded and how poorly recorded areas will inhibit examiners from being able to complete a proper examination and comparison of friction ridge detail.
Recording of Major Case Prints– This may be the last time that an individual’s friction ridge detail will be recorded it is important to acquire and record as much friction ridge skin as possible this includes fingers, joints, finer tips, palms and writers palms. A complete set of major case impressions will ensure that future examiners will have what is needed to do a complete analysis and comparison. Once a body is buried, cremated or complete decomposition has set in it will no longer be possible to go back and re-collect this information for future investigations.
In this section the instructor will demonstrate and describe the proper techniques for taking major case prints. The instructor will demonstrate how to use the different types of fingerprint cards needed to completely record all of the friction ridge detail located on the hands.
General Recording of Recently Deceased Subjects– This will be a hands on activity where the students will record major case fingerprints from recently deceased individuals.
This will include dealing with rigor mortis which may include either “breaking the rigor” which is forcibly straightening the digits or cutting the tendons in order to allow the fingers to be able to be recorded.
Using a fingerprint spoon with strips to record the friction ridge detail.
Putting black powder on the hands then lifting the impressions with fingerprint tape.
Recording Decomposed Friction Ridge Skin– If the skin has decomposed the friction ridge skin may be separated from the fingers and worn over the glove of the person recording the detail this is known as the glove technique.
Recording Macerated Friction Ridge Skin– Maceration occurs when skin has been softened due to excessive moisture. In these situations tissue builder or salt water maybe injected into the bulb of the finger to round out the pattern area and allow the impression to be recorded. Another technique is Osmotic Rehydration – The hot water will plump the dermis and allow the recording of friction ridge detail.
Tradition Rehydration – Can be accomplished by cleaning and soaking the fingers in water with hydrogen peroxide. Once the skin has softened the fingers can be dried then recorded.
Recording Rehydrated Friction Ridge Skin– If soaking and recording is not sufficient, the fingers should be thoroughly dried and injected with tissue builder then recorded. If the tissue builder is unsuccessful the powder and record technique can be used.
Recording Charred Friction Ridge Skin – Charring can occur when the body was subject to fire. This will cause the skin to become brittle and easily destroyed. One technique that can be used is the refrigeration of the skin and separating the epidermis from the dermal layer. The dermal layer will be recorded on a fingerprint card.
Course Outline:
8 am
Introduction, Objectives - Morphology of Fingerprints
Fingerprint Pattern Types and Requirements for recording friction ridge detail
Recording Major Case Prints
9 am
General Recording of Recently Deceased Subjects
10 am
Recording Decomposed Friction Ridge Skin
11 am
Recording Macerated Friction Ridge Skin
12 pm
LUNCH
1 pm
Recording Desiccated Friction Ridge Skin
2 pm
Traditional Rehydration Method of Deceased Friction Ridge Skin
3 pm
Recording Rehydrated Friction Ridge Skin
4 pm
Recording Charred Friction Ridge Skin
J.P. Rodriguez
Holding a Bachelors of Science degree from Florida State University, J.P. Rodriguez began his career as a Tenprint Examiner.
He has instructed the Basic Fingerprint Classification and Identification, the Basic Latent Print, and Advanced Latent Print and Comparison Workshops.
