Category Archives: Forensic Physics

CCTV Footage Importance as an Evidence

Full Form of CCTV: Closed-circuit TeleVision

Other Name: It is also known as Video Surveillance

Work: It uses video cameras and mike to transmit a signal to selected computers.

Admissibility of Electronic Evidences in Court: Electronic documents are admissible as material evidence. The computer generated electronic records in evidence are admissible at a trial if proved in the manner specified by Section 65B of the Indian Evidence Act.

Introduction: Nowadays CCTV cameras are one of the essentials and found almost everywhere; You can see it in malls, road, House, colleges, hotels, shop and many more places where security is needed. CCTV uses in Crime Scene Investigation: As we can find CCTV everywhere and it is capable to record videos in it’s range so it play a very important role in police investigation. With the help of CCTV many crime has been solved, many alibi has been made. CCTV used as an important security instrument by most of places so whenever anything happen it has been used as an instrument in solving the case.

Recently, Ballabgarh murder caught on camera! CCTV footage shows 21-year-old student shot dead in cold blood. CCTV footage was all over the media and every social site platform.

Fact of the case:

👉CCTV footage shows a girl named Nikita Tomar being shot dead by an assailant (Taufeeq) outside her college in Ballabgarh, Faridabad. Shooter and associate flees in car. Police have arrested Taufeeq and his associate. Will Footage will be consider as an direct evidence to prove suspect guilty? Lets know more about it:

Credibility of CCTV Camera in eye of Law: As an eye witness can’t be reliable too much because of his/her memory, turning hostile, may be bought or have any rivalry, CCTV also has its own problem, such as; bad video quality, no audio, blurred footage, etc. Still CCTV evidence has the potential to be conclusive enough to prosecute and CCTV footage is a strong piece of evidence but raw footage alone may prove to be inadequate so witness or other evidences are highly needed.

Question: What type of evidence is CCTV?

Answer: CCTV is a Circumstantial Evidence.

Question: What is a Circumstantial Evidences?

Answer:   Circumstantial evidence are those from which the desired conclusion may be drawn .  Circumstantial evidence is referred to as indirect evidence.

Role of Forensic Scientists

✍Work of Forensic starts from here. When the quality of the footage is poor, it can be very difficult to clearly identify the person visible in the video. There is technique named as Facial Mapping which can be used to identify the subject of the CCTV recording by comparing facial proportions and the distances between their features to a known image of a Person/victim/suspect. The findings of facial mapping can offer an indication of how likely it is that the person in the known image and the person in the CCTV image are the same. This work come under Forensic Physics Division.

Gait Analysis:

✍If the CCTV failed to capture the clear images, do not show the suspect’s face, then gait analysis can also be used to identify. Gait analysis means manner of walking is also studied in forensic science and used to track the person by comparison of actual walk with the video walk.

After applying all forensic applications and methods this alone can’t prove suspect guilty if other evidence and witnesses does not turned against the suspect.

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Glass Fracture Patterns

Question: what is importance of Broken Glass at Crime Scene?

Answer: Broken glass at crime scenes can play an important role in crime scene reconstruction, and it can be a very useful evidence. Glass fracture patterns are most often found at the following crime scene:

👉 Criminal Mischief,

👉 Burglary.

👉 Shooting Incidents,

👉 Fire Scenes, etc.

Photo by cottonbro on Pexels.com

Question: Which type of information can be obtained from analysis of broken glass?

Answer: Some common types of information can be obtained by studying glass fracture patterns:

1.) Direction of impact force applied (whether it is from inside out or outside in).

2.) Approximate force of impact.

3.) Approximate angle of impact of force.

4.) Determination of the type of glass fracture.

5.) Determination of the sequence of firing, direction of firing, and the type of firearm for the projectile holes present.

5.) Estimation of the fire temperatures, direction of fire travel, and the intensity of heat from the melted glass.

The use of glass fracture patterns in crime scene reconstruction relies on careful recognition, documentation, and study of radial and concentric glass fracture markings. Other information for reconstruction is obtained by analysis of rib marks, spatial relationships, crack marks, and the condition of any melted glass.

Photo by Thiago Matos on Pexels.com

Soil As An Evidence

Question:- Why soil is considered as an Evidence?

Answer:- Every type of soil has unique properties which act as an identification markers that’s why it plays important role in criminal investigation. Forensic scientists consider soil as any earth material that may lead to the conclusion or can help to reconstruct the crime scene and can be way to reach to the criminal. it can be stick to the tires, shoes, or foot or it can be unknowingly or knowingly stick to the clothes of victim or culprit. Soil forensics is considered as an important wing during investigations.


The basic components of soil are minerals, organic matter, water and air. But what do we need for forensic analysis in Soil, it includes rock, minerals, vegetation, glass, paint, asphalt, etc. Soil samples may also contain fossils or debris from human habitation and/or industrial operations, e.g. paint droplets, cinders, chemicals or fibers, however, these are rare but unique. The presence of these in that place helps to make that place of soil unique from others.

Question:- What quantity of soil sample is required ?

Answer:- In most forensics cases, only about one cup of the top layer of soil needs to be collected.

Question:- How soil samples should be collected?

Answer:- Collection tool materials: Tools for soil collection should be new or disposable items, such as; plastic spoons, swabs, wipes, filters. Nondisposable tools for softer materials (unconsolidated sand) may be made of plastic, but for harder materials, tools made of hardened or stainless steel are recommended.

Question:- How analysis should be performed?

Answer:- Samples are dried before testing, to prevent further decomposition of the material in the soil.

👉 At the crime lab, the forensic soil scientist conducts chemical and physical analysis tests and compares the soil samples from the crime scene location with the soil sample found on the suspect or on his or her belongings.

Microscopic Examination– Microscopic examination (Low Power Microscope) is an initial step in soil comparison. If unique foreign particles are found in soil samples which appeared similar in questioned and control sample then further examination will be needed but, if there is no similarity between these samples then no examination is needed.

Screening Methods– Simple and Rapid screening methods are required for soil analysis. Color Comparison and the determination of Particle Size Distribution can discriminate between questioned and control samples.

Instrumental Analysis-

X-Ray Powder Diffraction (XRD) Methods– XRD methods are arguably the most significant for qualitative, and semi-quantitative and quantitative analysis of solid materials in forensic soil science.

Scanning Electron Microscopes and Transmission Electron Microscopes– Scanning electron microscopes (SEMs) and transmission electron microscopes (TEMs) are frequently used to examine the morphology and chemical composition (via energy dispersive X-ray spectroscopy) of particles magnified by over 1,000,00 times, making these techniques very useful for discrimination.

Elemental Analysis– The following instrumental techniques are frequently used to determine the inorganic constituents in soil samples:

  • XRF ( (X-Ray Fluorescence);
  • Atomic Absorption Spectroscopy (AAS);
  • Neutron Activation Analysis (NAA);
  • Inductively Coupled Plasma (ICP);
  • Spectrometry, such as; Inductively Coupled Plasma-Optical Spectrometry (ICP-OES);
  • Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).
  • Fourier-transform infrared spectroscopy (FTIR) can be used to characterize soil organic constituents, for examples: fats, waxes, proteins, cellulose,hemicellulose, and lignin, etc. in soils.

👉 Another test for soil is Ground-Penetrating Radar Technology (GPR).
Ground-penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. Forensic soil Scientist use radar energy pulses to look for breaks in the soil’s structure. GPR helps detect anomalies in the soil, where radar energy is sent back to the receiving antennae. But it has the drawback that it is not always accurate, especially with heavy clay soils. In the end, with the use of soil forensics and GPR technology, scientists and investigators can make connections between differences in the soil and collected evidence. By identifying the individual characteristics of soil, investigators can use this knowledge to help solve crimes.

This final stage involves information from microscopic observations to the landscape scale, which may involve:

  • Soil classification and use of soil,
  • Geological,
  • And, vegetation maps; terrain analysis, remote sensing and geophysics, etc.

This combined information is used for geographic sourcing to identify the origin of a sample by placing constraints on the environment from which the sample originated.

FORENSIC PHYSICS (Introductory)

By @forensicfield

What is Forensic Physics?

Forensic Physics Deals With The Examination Of :

  • Computer & Mobile Forensics (Digital Forensics),
  • Audio & Video Processing,
  • Image Processing,
  • And Physical Evidences Etc.

What does Forensic Physics examine?

  • Density
  • Resistivity
  • Elasticity
  • Refractive Index
  • Temperature
  • Luminescence
  • Composition Of Various Physical Evidences.

What does Forensic Physics Include?

The Forensic Physics Comprises Of :

  • Basic Physics,
  • Electronics,
  • Ballistics,
  • Trace Analysis,
  • Accident Reconstruction,
  • Elements Of Photography,
  • And Study Of Various Instruments Used In Investigation And Analysis Of Evidences.

Which Type Of Physical Evidences Are Examined In Forensic Physics?

  • Paint
  • Glass– For example: Any window, Glass door, Glass bottle, Watch, Spectacles
  • Soil
  • FibersThese are mainly divided into two types: Natural fibers, Artificial fibers
  • Metallic Pieces
  • Threads
  • Tool Marks
  • Ropes
  • Obliterated Marks, etc.

What is the Major Part of Forensic Physics?

Another major part of Forensic Physics is Forensic Ballistics in which is study of the flight path of projectiles and firearms.

What does a Forensic Physicist Do?

Forensic Physicists examine the physical evidence gathered at crime scenes to help determine the nature of a crime and if there is any evidence indicating who committed it.

How is Physics used in Forensics?

This scientific technique involves using infrared photons to determine a particle’s vibrational mode. Since different substances have unique vibrations, forensic scientists can use this information to analyze crime scene evidence.

What is the Purpose of Forensic Physics in Crime Scene Investigation?

  • The Measurement Of Density (Soil And Glass Examination)
  • Index Of Refraction, and Birefringence (Fiber Analysis, Glass Examination)
  • Restoration of Vehicle Identification Number.
  • Building Material Analysis.
  • The Analog And Digital Electronics (Cyber Crime).

In What Type of Crime is Forensic Physics Used?

  • Cases of Accidents,
  • Firearm and Bullets Profile Analysis (Projectile Motion of a Firearm),
  • Glass Penetration of Speedy Stone,
  • Bullet or Tool Case Be Analyzed Using Physics,
  • Fire, Arson and Explosion Investigation,
  • Materials Identification (Fake Jewellery Etc.).
  • Software-based Imaging Methods For Facial Reconstruction, Etc.

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VIDEO IMAGE ANALYSIS

By @forensicfield

INTRODUCTION

In forensic Field Video image analysis is a new scientific technique for crime scene investigation.

With the help of Videos we can see real time incident. Video recordings can provide a real time eye witness of a crime which make investigation little bit easy for crime scene investigators.

For example- CCTV footage, hidden camera , etc.

In Parties, Riots, Fairs, Agitation, etc. video recordings are very common by people and media which help investigators to identifying the suspect of the crime etc.

Now a days almost every house, mall, shop have a cctv camera which can have footage of that particular place which also helps  in investigations .

Video analysis can be performed on recovered recording to answer the questions of “who” “what” “ when”, “where” and “How” in order to reconstruct an event.

Uses of Video Recordings or Video Image Analysis

1.Compare objects in different videos, or compare them with objects to determine similarity, differences or alterations.

2. Reconstruct incidents to understand the events preceding , during and after an incident.

3. Perform speed calculations to ascertain whether a vehicle was travelling below or above the road speed limit.

4. Present the findings and opinions clearly and effectively in an expert report that is admissible in the courts.

5. Sift out the details in the recording.

6. Fame-by-frame analysis.

Factors Affecting Forensic Video Analysis

1- Quality of video,

2- Distance of the object form the camera,

3- Its angle with respect to the camera,

4- Lighting,

5- Other environmental factors.

Techniques Used In Video Image Analysis

Repair and Recovery Of Evidence

Forensic experts are also able for repairing video evidence and can also recover the evidence like- CD’s, DVD’s , Cell phone, Video Cameras are Commonly used.

Tracking

By video analysis the images can be enhanced, slow down, enlarge to give a clear view of the recorded image and to track the CCTV footage.

Data Recovery

Digital video recorder (DVR) and the deleted retains can be analyzed and recovered.

Facial Comparison

The facial comparison of two or more images to provide a clear view of the criminal or victim is given by the forensic expert.

Height Calculation And Comparison

By video image analysis we can compare the height of unknown person recorded in CCTV footage can be determined.

Transcoding Service

This technique helps to see cctv footage more clearly in digital form.

Masking

it is possible to cover the face of some areas of the videos to protect the witness, victim or the police officers.

Video Stabilization

Reduces the amount of disturbances in the video producing the smoothness.

Sharpening

Sharpening makes images in the recording more clear.

To Corroborate Statements

In many cases video evidences can be used  to corroborate statements.

Evidence Enhancement

Forensic experts can enhanced a video recording, filters can be used to adjust the brightness of the image to correct to color etc. the speed of playback can be adjusted.

Unwanted noise can be removed.

Interlacing

The technique of combining to TV field to in order to provide a full frame of video.

De-Interlacing

A process called de-interlacing may be used to retrieve the information in both fields of video.

De- Multiplexing

In CCTV system a device called multiplexer is used to combined multiple video signals into single signals or separate a combined signals.

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