The Pune Rural Police have approached the court seeking permission to conduct a polygraph, commonly known as a lie detector test, on Siya Goyal, the main accused in the alleged murder of her 25-year-old fiancé, Ketan Agarwal.
Police allege that Ketan Agarwal was pushed into a nearly 400-metre-deep gorge at Lohagad Fort near Pune. Investigators claim that Goyal, along with alleged co-accused Chetan Chaudhary, planned the crime ahead of her scheduled wedding.
While a polygraph test cannot establish guilt, investigators believe it could help them uncover fresh leads in a case that largely depends on circumstantial and digital evidence.
Also Read | Ketan Agarwal murder case: How a hoodie in 33°C heat turned an accident probe into a murder investigation
Why are police seeking a lie detector test?
According to investigators, the probe has been complicated by several challenges.
Police say there are no eyewitnesses or CCTV cameras capturing the exact location where the incident took place. They also claim the accused deleted call records and even cleared items from their phones’ recycle bins before and after June 18, allegedly attempting to erase digital evidence.
Officials have further stated that conflicting statements from the suspects and their family members regarding the wedding preparations have made it difficult to establish the alleged motive.
The police hope the polygraph examination may help verify existing evidence, identify inconsistencies in statements, generate fresh investigative leads, or help recover material evidence that can later be independently verified.
How does a polygraph test work?
A polygraph does not detect lies directly. Instead, it records physiological changes that may occur when a person experiences stress while answering questions.
During the examination, pneumograph tubes monitor breathing patterns, a blood pressure cuff records heart rate and blood pressure, and galvanometric electrodes attached to the fingertips measure changes in skin conductivity caused by sweating.
Before the test begins, the examiner explains the procedure and reviews the questions with the subject. The session typically includes irrelevant questions, control questions and questions directly related to the alleged crime. The examiner then compares physiological responses across these categories.
Is a lie detector test legal in India?
Yes, but only with voluntary consent.
In its 2010 judgment in Selvi v. State of Karnataka, the Supreme Court ruled that involuntary polygraph, narco-analysis and brain mapping tests violate Article 20(3), which protects against self-incrimination, and Article 21, which guarantees personal liberty and privacy.
The subject’s consent must be recorded before a Judicial Magistrate, legal counsel must be available before consent is given, and the examination must be conducted at an authorised forensic facility.
Also Read | What is gait analysis? The key test in the Ketan Agarwal murder probe
Are polygraph test results admissible in court?
The results of a polygraph test are not admissible as substantive evidence and cannot be treated as a confession or used alone to secure a conviction.
However, if information voluntarily shared during the examination leads investigators to discover new facts or physical evidence, that material may be admissible under Section 27 of the Indian Evidence Act, subject to the court’s scrutiny.
At present, both Siya Goyal and Chetan Chaudhary remain in police custody. Their counsel has stated that the accused are willing to cooperate with the investigation and undergo a polygraph test, subject to the legal process.
FAQs:
Is a lie detector (polygraph) test legal in India?
Yes, but only with the accused’s voluntary consent, and its results are not admissible as direct evidence in court.
Can a polygraph test help solve the Ketan Agarwal murder case?
The test cannot prove guilt but may help investigators develop fresh leads or recover evidence that can be independently verified.
