Crime Scene Investigation Overview

The area where the crime took place and evidence is most likely to be compromised.

A larger area surrounding the inner perimeter that is established to manage and protect the crime scene.

First responders, like police officers, who arrive at a crime scene and initially secure the area.

The officer in charge of managing the investigation at a crime scene and meeting with the team for a briefing upon arrival.

A specialist trained to collect and document evidence at a crime scene, who arrives after the initial securement of the scene by responding officers.

A crucial step in ensuring admissibility of evidence in court. It involves securely managing the crime scene area, controlling access, and protecting evidence integrity.

The organized process of examining and documenting a crime scene to collect evidence and reconstruct the events.

A systematic approach involving different methods and techniques for searching a crime scene to uncover evidence.

The circumstances and details of the crime scene area, captured in the notes, including weather, temperature, lighting conditions, and any other relevant environmental factors.

A record of the initial assessment of the crime scene by the CSI team, documenting the observation of any potential evidence or points of interest.

An accurate and detailed record of the victim's physical characteristics, including any injuries, clothing, and position at the scene.

A systematic process of documenting all evidence found at the crime scene, including its location, description, and any changes made to its original state.

Notes taken at the crime scene should be meticulous and comprehensive, including all observations and actions. The notes should be clear, legible, and free of erasures or alterations.

The date and time the CSI team received notification of the crime, the method used to deliver the notification, and the preliminary details provided about the crime scene.

Details about the initial walkthrough, including the date, time, participants, and any evidence identified during this preliminary assessment.

A descriptive record of the crime scene location, including the surrounding area and any significant features, such as buildings or landmarks.

A permanent record showing the size, distance relationships and location of all the crime scene evidence.

A quick sketch, completed during the initial walkthrough of the crime scene. Serves as a foundation for the final sketch.

A detailed and polished version of the rough sketch, prepared for presentation in court.

A visual representation of a room or series of rooms, providing a bird's-eye view.

A vertical plane, often used for staircases or blood spatter patterns on walls.

A visual representation of an outdoor crime scene, providing a bird's-eye view of the area.

A combination of floor plan and elevation, providing a thorough representation of the crime scene.

A method of taking measurements from two fixed points to the location of evidence.

A method of measuring distances along a fixed line, then perpendicular to that line towards evidence.

A method of recording a crime scene using a measuring tape and compass, measuring distance and direction from a reference point to the evidence.

Measuring the distance of an object from a reference point at a right angle. Used in crime scenes to create an accurate representation of the scene.

A method of creating accurate measurements of objects in photographs by using objects of known size and special software. It helps to reduce distortion by using overlapping photos.

A continuous, documented record that shows the history of evidence from the moment it is collected to when it reaches the court. It proves the integrity of the evidence and ensures its admissibility.

A method used to ensure that evidence has been properly collected and handled. It involves documenting every step of the evidence's journey, from collection to analysis and finally, to the courtroom.

A method of searching a crime scene where the area is divided into horizontal strips, often overlaping to increase thoroughness.

Similar to the strip method, but searchers cross the area twice, creating a grid pattern. This increases the chance of finding small or overlooked evidence.

A method that focuses on the connections and relationships between different pieces of evidence. It's not based on a geometric pattern and is instead driven by logical inference.

Used for scenes with defined zones, like rooms in a house. Each zone is searched systematically, using other search patterns within each zone.

A method where searchers move outward from a central, critical point in straight lines, like rays from the sun.

A method where searchers move in a spiral pattern either inward toward a critical point or outward from it. Effective for open, barrier-free areas.

A unique search involving the interior, exterior, undercarriage, and the location where the vehicle was found. Process typically includes towing the vehicle for thorough and safe investigation.

The main goal of crime scene investigation is to gather information, preserve the crime scene context, and document evidence to understand what happened.

A critical aspect of crime scene documentation, note-taking begins before arriving at the scene and continues as events unfold. It should be detailed and comprehensive, preserving the original sequence of events.

Notes provide a permanent record of the crime scene, potentially crucial for future investigations. Even seemingly insignificant details can be significant later.

These include details such as notification information, arrival time, initial observations of the scene, and any preliminary actions taken.

The first phase of documenting a crime scene typically involves a visual overview, recording overall observations and potential points of interest before a more detailed examination.

Systematic, thorough documentation of a crime scene through note-taking, videography, photography, and sketching, creating a permanent record of evidence and context.

Four key methods used to document a crime scene, usually performed in sequence, capturing the scene before evidence collection.

These four methods are typically performed in a specific order to ensure a complete and accurate record of the crime scene.

Documentation is important because it acts as a permanent record of the crime scene, preserving its context and evidence for future reference.

Mitochondrial DNA (mtDNA) is a type of DNA found in the mitochondria of cells. It is inherited only from the mother and is present in multiple copies within each cell.

Presumptive tests are simple, quick tests used at crime scenes to determine if a specific substance is present. They help prioritize areas for further investigation.

Confirmatory tests are more complex and specific lab tests used to confirm the presence of a substance. They provide conclusive results required for legal proceedings.

Luminol is a chemical reagent used in crime scenes to detect blood even in diluted form. It glows when it reacts with iron in hemoglobin, making blood visible.

Bluestar is a newer chemical reagent that has replaced Luminol in many crime scenes due to its advantages. It's less toxic, works in less darkness, and gives a stronger, longer-lasting reaction.

Hemastix is a test strip originally used for blood in urine. It changes color based on the presence of blood, but it's not ideal for crime scenes as it can interfere with DNA analysis.

Phenolphthalein (Kastle-Meyer) is a presumptive test for blood that utilizes a reagent and hydrogen peroxide. It turns pink in the presence of blood, but false positives can occur with some substances.

Presumptive tests for blood often rely on the presence of hemoglobin, an oxygen-carrying molecule found in blood. They exploit the chemical properties of hemoglobin.

It's crucial to never directly apply chemicals to a bloodstain. Instead, use a sterile swab or filter paper to collect the sample and then apply the chemical to the swab.

When performing presumptive tests, it's essential to use both positive and negative controls. Positive controls ensure the test works correctly, while negative controls confirm no other substances are causing false positives.