Comprehensive Study Guide for Criminalistic Techniques

Conceptual Foundations and the Criminalistic Trace Kriminalistick!štick!š stopa (Criminalistic Trace) is defined as any change in the material environment or in human consciousness that is locally, temporally, or causally related to the investigated event. This trace contains criminalistic or criminal law information and must be detectable. The information derived from these traces is utilized through criminalistic, scientific, and technical methods, tools, and procedures. A criminalistic trace originates when a perpetrator leaves something behind, takes something, or changes something during the commission of an act. Examples of these actions include leaving a fingerprint, a drop of blood, or a hair, or physically changing the environment, such as by breaking a window. Criminalistic traces are classified into several categories. Memory traces (Pam!ě!ťov!é) consist of visual, auditory, olfactory, and gustatory perceptions stored in human consciousness. Material traces (Materi!áln!í) are those created anywhere outside of human consciousness, including traces on the human body itself. Material traces are further divided into static traces, which can be layered (navrstven!é) or unlayered (odvrstven!é), and dynamic traces, such as grooves, abrasions (se!šinut!í), or bruising (zhmo!ž!ě!šn!í). Traces are sought using sight, touch, technology, and specialized methods. The documentation and securing of traces follow a specific six-step procedure: 1. Securing the crime scene (closing the area to prevent destruction); 2. Photography (carefully documenting everything in its found state); 3. Description (recording location and appearance); 4. Securing the traces (collecting items using tweezers, brushes, foil, or bags); 5. Labeling (assigning numbers and descriptions to prevent loss or confusion); and 6. Transport (safe delivery to the laboratory for analysis). Key institutions for trace analysis include the Criminalistic Institute Prague (K!Ú!­), which is the largest and most important facility examining fingerprints, DNA, drugs, weapons, forgeries, and fires, and the Regional Criminalistic Laboratories (KKL), which handle common traces within specific regions. # Dactyloscopy: The Science of Papillary Lines Dactyloscopy is a scientific branch of criminalistic technique that examines the patterns of papillary lines on the inner side of the last joints of fingers, palms, toes, and soles. Its purpose is the individual identification of persons based on the laws governing these patterns. Three fundamental laws govern dactyloscopy: first, the uniqueness law (no two individuals in the world share identical patterns); second, the immutability law (patterns remain relatively constant throughout a person's life); and third, the indestructibility law (patterns cannot be removed unless the germinal layer of the skin is destroyed). Dactyloscopic traces originate through physical contact between papillary lines and an object, with the adhesion of the print depending on the surface. These traces are categorized as Volumetric traces (soft substances deformed by fingers), Unlayered traces (substances like blood, paint, or dust transferred from a surface to the finger), Layered traces (substances transferred from the finger to a surface), and Latent traces (invisible prints formed by sweat or chemical substances). Finding these traces involves several methods. Physical methods rely on the differential adhesion of sweat components to powder particles such as graphite, argentorate, fluorescent, magnetic, or nano powders. Chemical methods involve reactions between sweat components and chemicals to produce colored compounds, such as Ninhydrin or DFO (diazo-fluoren). Physicochemical methods utilize the adhesion of chemical compounds like iodine vapors or cyanoacrylate. Special methods include the use of argon lasers to induce luminescence in sweat residue, though this method can be destructive and degrading to the sample. Securing dactyloscopic traces can be done In Natura (sending the object and trace together), via dactyloscopic tapes and foils (the most common method at crime scenes), through photography with a scale and numerical identification, or by casting for plastic prints (using silicone rubbers like Lukopren or Isomark). In dactyloscopy, identification points called minutiae (markanty) are used, which include types like beginnings/endings, short lines, bifurcations (vidlice), eyes (o!čko), hooks, bridges, and crossings. The usability of a trace depends on the number of these features: traces with at least $10$ identification signs are usable as legal evidence; traces with $7-9$ signs are partially usable for tactical information but not as evidence; and traces with fewer than $7$ signs are unusable due to small area, smudging, or degradation. Automated systems used include AFIS 2000, AFIS-BIS, AFIS cBIS (containing approximately $800,000$ cards), and EURODAC. # Trasology: Analysis of Impressions and Tracks Trasology is the field of criminalistic technique involved in searching, securing, and examining traces of bare feet, footwear, transport vehicles, and similar objects. Objects of study include footprints, tire tracks, tool marks (crowbars, screwdrivers), hand impressions (other than fingerprints), animal tracks, tooth marks, and ear prints. Trasological traces are categorized as Volumetric (three-dimensional) or Surface (two-dimensional). Surface traces can be layered or unlayered and may be visible or latent. These traces are created by pressure, pull, or movement across a surface. In the field or indoors, search methods must be systematic. Surface traces are often found using oblique (grazing) lighting, while volumetric traces are common in outdoor terrain. All traces must be protected from environmental degradation. Securing methods include In Natura (securing the whole or part of the object), Photography (always with a scale and good lighting), and Casting (using alabaster plaster or synthetic materials like Lukopren or Tewesil, specifically for traces susceptible to heat). The primary system used is TRASIS, which consists of a catalog of control shoe sole prints and a collection of traces secured from crime scenes. # Criminalistic Biology and Forensic Genetics Criminalistic Biology is an independent branch that deals with the searching, securing, examining, and evaluating of biological materials. A distinction is made between biological material (anything that was or is part of or a product of a living organism) and a biological trace (biological material secured in connection with a forensically relevant event). Common types of biological traces include blood (drops, sprays, streams, puddles, smears), saliva, sweat, semen, hair, fur, skin, bones, teeth, urine, and amniotic fluid. These traces originate when a person intentionally (fighting, spitting) or unintentionally (injury, sweating, hair loss) leaves biological matter at a scene. For searching, experts use visual inspection, light sources (UV and infrared), chemical tests, and swabs. Securing must follow strict rules: document the trace first, secure the whole object if possible, package objects separately in clean/sterile containers, secure as much material as possible, ensure strict cleanliness of tools (scissors, tweezers, tubes), avoid touching traces with bare hands, and send perishable materials for analysis as quickly as possible. External factors such as heat, sunlight (UV radiation), humidity, rain, water, wind, chemicals, and time can cause degradation of biological traces. Examination methods include blood tests (orientation vs. specific tests), microscopy, biochemical tests, and DNA analysis. Related forensic branches include Forensic Genetics (DNA from blood, saliva, hair), Forensic Medicine, Forensic Anthropology (identification via skeletal remains), Forensic Odorology (identifying remains in significant decay), and Forensic Entomology (using insects to determine facts like time of death). # Portrait Identification Portrait Identification is the field of criminalistic technique that identifies humans based on external features for searching for persons and identifying unknown individuals or corpses. External features are divided into automatic (static) features, determined by body and facial structure, and functional (dynamic) features, such as posture, gait, gestures, voice, and facial expressions. Functional features are described during movement and can change due to environment, fatigue, illness, stress, or alcohol. Facial features are evaluated morphologically/qualitatively (shapes of nose, lips, etc.) and metrically/quantitatively (measurable distances). They are further classified by evidentiary value as general (group) or specific (individual), and by relative variability (negligibly variable vs. variable with aging, such as hair loss or wrinkles). Portrait identification can be official (prepared by a specialist/technician using tools like scales and samples) or layperson-based (obtained by interviewing witnesses or victims). Official descriptions cover height, weight, build, apparent age, head shape (oval, round, etc.), skull shape, hair, beard, forehead, eyes, and more. Methods for composing portraits include graphic methods (drawing), plastic methods (modeling, though no longer used), the Gerasimov method (reconstruction based on the skull), fotorobot (sets of photographs), and the Facette program (containing over $4000$ facial elements). In the Czech Republic, the wPORIDOS system (used by PČ!Ř since $2014$) creates an identikit from real photographs. Strict principles must be followed: the composer must be trained, patient, calm, and empathetic, avoiding distractions and using specific questions. If the victim or witness is under $18$, a legal guardian or social worker must be present. Negative circumstances include extreme stress of the witness, conflicting identikits for the same perpetrator, untruthfulness, or technical failure. # Mechanoscopy and Tool Mark Examination Mechanoscopy is the branch of criminalistic technique studying the laws of creation, duration, and disappearance of traces made by tools and technical means. It aims to identify the tool and how it was used. Tools are classified as Cutting (knives, saws), Stabbing (screwdrivers, axes), Prying (crowbars), Striking (hammers), and Shearing (scissors, pliers). Trace types include surface traces (visible or latent), indents (static volumetric traces from impacts), grooves/scratches (dynamic volumetric traces from lockpicks), abrasions (se!šinut!í - systems of grooves from sawing or drilling), bruising (irregular shapes from repeated strikes), and tool particles (from grinding or drilling). Objects of examination include tools, locks, seals, and fragments of tools or glass. Securing traces is primarily done In Natura. If the carrier cannot be taken, casting with polymers or silicones (LUKOPREN, MIKROSIL) or photography with a scale is used. Secure tools must be separated by paper or card to prevent movement during transport, and packages must be sealed and stamped. Locks are categorized by construction (ordinary, dog-lock, butterfly, cylindrical), security level, mounting (surface, mortise), and use (left, right, universal). Methods to overcome locks include lockpicking (plan!žeta), the bumping method (SG method), the Rescop W system for plastic doors, or physical destruction of the cylinder body. # Odorology: Scent Identification Odorology is the forensic study of identifying persons or things based on scent. It examines the properties of human scent, drugs, explosives, and other relevant substances. Human scent traces and traces from things or plants are the two primary types. Because scent traces are invisible and fragile, they must be secured first at a crime scene. Identification methods are divided into Objective (olfactorics), involving lab technology, and Subjective (olfactonics), using specially trained dogs. The most common subjective method involves scent jars (pachov!é konzervy). A comparison scent is taken by placing scent sensors on a suspect’s bare skin (side/waist) for at least 20!  ext{min}. The suspect must not touch the sensor. For In Natura securing, the carrier is placed in ARATEX, wrapped in foil for 20!  ext{min}, and then moved to a scent jar. The process results in a formal expert statement (Odborn!é vyj!ád!řen!í). # Examination of Documents, Securities, and Currency This field aims to establish facts of evidentiary importance regarding written documents, public certificates, securities, and currency. Documents (Listiny) include wills and contracts. Public documents (Ve!řejn!é listiny) are issued by authorities (birth certificates), courts, or universities (diplomas). Securities (Ceniny) are used for fees (stamps), services (tickets), or goods (gift vouchers). Currency (Platidla) consists of notes and coins. Examinations determine how an object was made (original vs. copy), how it was altered (mechanically or chemically), what writing tools were used (ink analysis), and the original content of damaged items (burned or soaked). Technical protection includes paper properties (watermarks, fibers), printing techniques (microprint, UV ink), and mechanical/electronic features (magnetic strips). Modern protection includes giloches, kinegrams (which change hue when rotated $180^{\circ}$), EURion constellations, and iridescent strips. Forgeries are classified by danger levels: level $5$ (unskilled), $4$ (less successful), $3$ (successful), $2$ (dangerous), and $1$ (very dangerous). Text removal can be mechanical (erasing/scraping) or chemical. Documentation must be sent for examination in its original state without added notes or marks. # Criminalistic Ballistics Ballistics examines weapons, ammunition, discharge by-products, and shot effects to identify weapons and clarify shooting conditions. It is divided into: Internal Ballistics (studying the projectile inside the barrel); Transitional Ballistics (movement immediately after leaving the barrel until gas effects cease); External Ballistics (flight through space, including trajectory, energy, and speed); and Terminal/Wound Ballistics (movement and effects in the target). Objects of study include mechanical weapons (bows), gas weapons (airguns), and firearms (most common). Ammunition components for bullet cartridges include the bullet, casing, powder, and primer; shotgun shells include wads (plst!ě!šn!á z!átka) and multiple shot. Traces form on the casing and bullet during firing from specific functional parts of the weapon. At a crime scene, weapons must be unloaded before securing. By-products like flames, soot, and powder grains are documented. Techniques like BalScan assist identification. Shooting effects are categorized as: Through-and-through (průstřel - enters and exits); Entry (zastřel - enters and stays); Surface strike (n!ástřel - lacks energy to penetrate); and Tangential strike (postřel). Trigger resistance is tested to determine intent vs. accident and compatibility with witness statements. # Handwriting and Script Analysis This discipline examines human written expression to identify the writer or author. Handwriting analysis (P!ísmoznalectv!í) is a forensic field focused on identification, whereas Graphology is a branch of psychology focusing on personality. Objects include the script, writing process, and text. Script types include block letters (hůltkov!é), cursive, pearl script, or individual combinations. Factors affecting handwriting include Internal factors (anatomy, physiology, motivation) and External factors (environment, writing position, tool quality). Analysis utilizes Questioned materials (disputed signatures or altered texts) and Comparison materials (exemplars known to be from the suspect). Examination occurs at a General level (layout, addressing) and a Special level (multicomponents and individual stroke components).