Polygraph Test: A Forensic Approach to Lie Detection

 Polygraph Test or Lie Detector Test was introduced in Bangladesh for the first time by our Company, BIFPS Consultancy Ltd. (ForensicBD™).

For the first time in Bangladesh, we bring it and introduce the Polygraph Test as a professional truth-verification service. As the country’s first and only institution to offer this service, ForensicBD™ brings internationally recognized forensic methodologies to Bangladesh.

What is a Polygraph Test?

A Polygraph Test, commonly known as a Lie Detector Test, is a scientific evaluation method used to assess truthfulness by analyzing an individual’s physiological responses while answering specific questions.

How Does a Polygraph Test Work?

The polygraph instrument simultaneously records multiple physiological changes, including:

1. Heart Rate

2. Blood Pressure Respiration Rate

3. Skin Conductance (sweat or electrodermal activity)

4. Subtle changes in pupil size (Pupillary Response)

When a person tells a lie, internal psychological stress is generated, which causes involuntary physiological changes. These reactions are controlled by the Autonomic Nervous System, which operates automatically and cannot be consciously controlled by the individual.

A certified Polygraph Examiner analyzes these recorded responses and provides an objective and professional opinion regarding truthfulness.

Our Polygraph System Includes We use a state-of-the-art computerized polygraph system, consisting of:

1. CPS Elite System with Electronic Pneumos

2. CPS Plethysmograph

3. CPS Elite Complete Movement Sensor Package, including:

i) Masseter Headset

ii) Arm Sensors

iii) Feet Sensors

iv) Seat Sensor

This advanced configuration ensures high accuracy and comprehensive physiological monitoring.

Stages of the Polygraph Test –

1. Pre-Test Interview:  Before the examination, the individual is fully briefed on the procedure. At this stage, our institution conducts Body Language Analysis and Psychological Profiling to collect relevant background and behavioral data.

2. Polygraph Examination: Specific test questions are carefully formulated. The examinee is interviewed while physiological responses are recorded simultaneously using the polygraph system.

3. Data Analysis: The collected data is analyzed using standardized charts, graphs, and computerized reports.

4. Final Opinion: After detailed analysis, examiners provide their professional and impartial opinion based on the findings.

Applications of the Polygraph Test:

Polygraph testing is effectively used in many countries for various purposes, including:

i. Suspicion verification,

ii. Marital, extramarital, and family disputes

iii. Corporate fraud and internal investigations

iv. Criminal investigations

v.  Employee screening and job verification

vi. Legal and investigative support assessments.

 Is the Polygraph Test Admissible in Court?

In many countries worldwide, polygraph testing is widely used. Although it is generally not accepted as primary evidence, it is often considered supporting evidence that helps guide investigations in the right direction.

Countries where polygraph tests are used in government and private sectors include the United States, Mexico, Russia, Israel, South Africa, Ukraine, Japan, and India, among others.

Advantages of the Polygraph Test:

i. Accelerates investigations

ii. Assists in identifying deceptive statements

iii. Helps reduce psychological pressure on innocent individuals

iv. Increases the likelihood of obtaining truthful disclosures.

Who Conducts the Polygraph Test?

Polygraph tests are conducted by trained and certified Polygraph Examiners with advanced qualifications in Psychology and Forensic Science.

At ForensicBD™, the Head of Polygraph Test Investigation is Md Meraz Hossain, a Forensic Psychologist.

Conclusion: The Polygraph Test is a scientific, analytical, and supportive assessment tool that plays a significant role in truth verification. However, it should always be used alongside professional analysis and corroborating evidence.

⚠️ Important Note: The individual undergoing the polygraph test must participate voluntarily. Prior to testing, ForensicBD™ prepares comprehensive Interviewing Data through Psychological Profiling and Body Language Analysis. And finally, The Polygraph Test Report is provided after a specified evaluation period.