Lie Detectors, Narco Tests & Crime Scene Secrets: Forensic Expert Dr. Anita Evangeline Uncovers the Truth
In this interview episode of “Radhika On Record” (by Telugu Post Originals), host Radhika sits down with Dr. Anita Evangeline, retired Additional Director of the Telangana State Forensic Science Laboratory (TSFSL). Over a career spanning more than 31 years (having joined service in 1993), Dr. Anita earned over 12 academic degrees across diverse fields including criminology, psychology, crime and criminal justice, and law driven by a passion to understand the deeper mechanics of criminal justice.
In this discussion, Dr. Anita offers a detailed breakdown of the internal workings of forensic science laboratories. She explains how physical evidence, biological traces, document examination, ballistics, and advanced psychological evaluations such as polygraph testing, narco-analysis, and brain fingerprinting serve as critical investigative aids for law enforcement. Through real-life case studies ranging from the Lalaguda assault case, the Nehru Zoological Park tiger murder, and the Vanasthalipuram infant homicide, to national high-profile cases like Aarushi Talwar, Ajmal Kasab, and ND Tiwari, Dr. Anita outlines both the power and the legal limits of forensic science in modern criminal justice.
1. Career Journey & Educational Background
Radhika: Welcome to the show, ma’am! When I looked at your name and designation, I was truly impressed—you hold over 12 academic degrees across psychology, law, and criminology. How did your journey in forensic science begin, and how was all of this academic background possible?
Dr. Anita Evangeline: Thank you, Radhika. When I received my call letter and joined the department back in 1993, I honestly didn’t even know what the word “forensic” meant,I had to search for its definition because awareness was so limited back then. Over time, as public awareness grew, I completed my probation and was attached to various lab sections. As I analyzed cases and saw how our lab reports directly impacted real investigations, I felt deep job satisfaction. To better understand the entire machinery of law, I pursued a Diploma in Crime, Criminal Justice, and Forensic Science. That started a chain reaction ,I kept adding degrees in criminology, psychology, and law to supplement my hands-on lab experience. Today, I hold more than 12 degrees.
2. Crime Scene Evidence Collection & The “Ice Cube” Metaphor
Radhika: From the crime scene to the Forensic Science Laboratory (FSL), how many types of physical evidence exist? Is there an ideal travel time, and does a delay affect the final analysis?
Dr. Anita Evangeline: Absolutely, delay significantly impacts the results. Let me give you an example using an “Ice Cube Metaphor”. Suppose I place an ice cube in your hand on a hot summer day and ask you to deliver it to someone down the road. Everyone sees me hand you an ice cube and can witness to it. But by the time you walk through the heat and reach the recipient, the ice has melted into water. The recipient won’t say you gave them ice; they will say you brought water.
Forensic evidence behaves the exact same way. Biological evidence decomposes or transforms into secondary metabolites if left exposed. For instance, snake venom proteins degrade into other metabolites over time, making laboratory identification impossible. Similarly, bloodstains on a busy traffic road get contaminated or destroyed by passing vehicle tires if not collected immediately. You only get one chance at a crime scene.
Radhika: How does the investigation team ensure that crime scene evidence isn’t destroyed before collection?
Dr. Anita Evangeline: The moment a Police Station (PS) receives information about a crime, the local Clues Unit and Investigating Officer (IO) dispatch to the scene. Their very first step is to safeguard and cordon off the area using “DO NOT CROSS” tape. This keeps curious onlookers out so they don’t destroy footprints, footwear impressions, or bloodstains. It also protects physical evidence from weather exposure (rain, wind) or stray animals.
Once secure, evidence is collected alongside a control sample following the Law of Comparison. For example, if we find a suspicious stain, we collect the stain as well as an unstained control sample from the adjacent surface to verify what the background material is.
3. Biological Evidence: “Blood vs. Tomato Ketchup” & Real Cases
Radhika: How do you verify whether a suspicious red stain is actually human blood?
Dr. Anita Evangeline: People often assume any red stain is blood, but in forensics, we follow preliminary and confirmatory tests. First, we establish if it is blood; second, if it is human or animal; and third, the blood group or DNA profile.
We’ve seen surprising cases:
The Tomato Ketchup Case: In one instance, police sent a glass slide with a thick red substance, convinced it was blood. When we analyzed it in the lab, it tested completely negative for blood—it was actually Maggi Tomato Ketchup!
The Five-Year-Old Girl Case: In a molestation case involving a 5-year-old girl, police sent a shirt covered in red stains. Analysis revealed it wasn’t human blood at all, but chicken blood.
The Lalaguda Chicken Shop Case: A 7-year-old girl was sexually assaulted. The child was traumatized, but later pointed toward the local chicken shop owner. When police questioned him, he claimed the blood on his apron was purely chicken blood from his shop. However, our Serology and DNA analysis proved that the blood on his apron matched the vaginal swabs and inner garments of the young victim, disproving his claim and pinning the perpetrator.
Radhika: Why is blood grouping alone not enough to convict someone?
Dr. Anita Evangeline: Because common blood groups like B-positive are shared by a large percentage of the general population. Just because a suspect has B-positive blood doesn’t make them the killer. That is why we advise police via the Letter of Advice to request DNA profiling, which provides a unique genetic match to link the suspect, victim, and crime scene.
4. Forensic Botany & The Missing Wheat Truck Mystery
Radhika: What divisions exist within the Biological Wing of the FSL?
Dr. Anita Evangeline: The Biological Wing has three primary sections: Biology/Botany, Serology, and DNA.
In Biology/Botany, we analyze plant matter, diatoms, hair, fibers, and even chilli powder used in robberies. A fascinating example from early in my career involved a missing government ration wheat truck. Several trucks carrying subsidized wheat imported from North India were traveling together in a convoy to Hyderabad. At one check-post, officers realized one truck was missing. Back then, there were no CCTV cameras or GPS trackers.Months later, an astute police officer investigating the cold case noticed a distinct, straight line of small germinating wheat plants growing along the roadside dirt. He followed this germinated plant trail off the main road, which led him to an abandoned, unused shed. Inside the empty shed, officers found a few leftover wheat grains swept into the corners. They collected those grains and sent them to our lab. Our scientists cultivated those grains alongside control wheat samples from the original batch. By comparing the botanical species and growth traits, we officially confirmed that the abandoned wheat belonged to the exact missing convoy batch, allowing police to track down the hijackers.
5. The Nehru Zoological Park “Sakhi” Tiger Murder Case
Radhika: Wasn’t there also a famous case involving a tiger at the Hyderabad Zoo?
Dr. Anita Evangeline: Yes, the murder of ‘Sakhi’, a Royal Bengal Tiger at the Nehru Zoological Park. One morning, zoo officials discovered Sakhi lying dead inside her enclosure, completely skinned like a dressed chicken. It was a massive national shock. Investigations revealed that insiders had temporarily turned off the enclosure’s electric fencing.
Skin and hair samples recovered from suspects in the Old City were sent to our lab. We examined the hair under high-power microscopes to establish its origin—differentiating human hair from animal hair, male hair from female hair (based on cortex, medulla, thickness, and smoothness), natural hair from dyed hair, and genuine tiger hair from synthetic fur. Our microscopic evidence confirmed the recovered hide was authentic tiger skin, proving the involvement of the poaching ring.
6. DNA Profiling, Mass Disasters, & “Who is the Mother?”
Radhika: How does DNA profiling help in mass disasters or complex disputes?
Dr. Anita Evangeline: DNA profiling provides definitive identification:
The Mahabubnagar Palem Bus Disaster: A Volvo bus caught fire, burning over 40 passengers beyond recognition into charred bone fragments and tissue. Families desperately wanted the remains of their loved ones for final rites. Our DNA team worked day and night in shifts, extracting DNA from bone fragments and matching them against the reference blood samples of parents and close relatives to correctly segregate and hand over the remains.
Locard’s Exchange Principle: Formulated by Edmond Locard, this foundational forensic principle states that when two objects come into contact, there is an inevitable exchange of matter. In a hit-and-run, paint chips and glass transfer between vehicles. In sexual assault cases, hair, saliva, sweat, or clothing fibers transfer between perpetrator and victim.
Resolving “Who is the Mother?”: While DNA is traditionally associated with paternity disputes (“Who is the Father?”), we also use it to resolve maternity disputes (“Who is the Mother?”). In hospital maternity wards, due to staff negligence or greed, male and female newborn babies sometimes get swapped (Baby Swapping). When two mothers both claim a male infant, we perform DNA profiling comparing the baby’s DNA against both mothers to conclusively establish the true biological mother.
7. Physical & General Divisions: Document Forgeries & Secret Jail Letters
Radhika: What about non-biological evidence, like documents, firearms, or digital files?
Dr. Anita Evangeline: That falls under the Physical Division and General Division:
Document Section: Examines simulated forgeries, handwriting, signature alterations, and cheque fraud (e.g., chemically erasing or adding zeros to turn 1 lakh into 10 lakhs). Everyone has unique class and individual writing characteristics,such as whether you form the letter “S” starting from the top or the bottom. We also decode indented writing,the impressions left on an underlying pad when someone writes on the top page,using charcoal powder or specialized optical instruments.
Invisible / Secret Writing in Prisons: Inmates attempting to bypass jailor scrutiny write normal letters in ink, but insert hidden messages between the lines using invisible, colorless liquids like onion juice, milk, Sprite, or saliva. Once dry, the text is completely invisible to the naked eye. However, when exposed to Ultraviolet (UV) light or mild heat, the secret coded text fluoresces and becomes fully readable.
Ballistics & Physics: Determines shooter range, bullet trajectory, weapon identification, and analyzes hit-and-run tire/footwear impressions.
General / Digital Division: Examines digital evidence—laptops, mobile phones, CCTV footage, audio/video authenticity, and photo morphing.
8. Psychological Testing: Polygraph vs. Narco-Analysis vs. Brain Fingerprinting
Radhika: Movies like Super show lie detectors buzzing or flashing red lights when someone lies! Is that how psychological testing actually works?
Dr. Anita Evangeline: Movies dramatize it for comedy, but real science is very different. When there is no physical evidence (“Corpus Delicti”) at a crime scene, or when statements need verification, police rely on the Psychological Division.
There are three distinct tests, each with strict operational boundaries:
+————————+————————————+———————————-+
| Feature | Polygraph (Lie Detector) | Narco-Analysis |
+————————+————————————+———————————-+
| Administered State | Fully Conscious | Subconscious / Trance |
| Location | Forensic Laboratory | Hospital Operation Theatre (OT) |
| Personnel Present | 2 Persons (Examiner & Subject) | 4-5 Persons (Anesthetist, |
| | | Physician, Psychologist, etc.) |
| Primary Mechanism | Physiological Sensors & Polygrams | Drug: Sodium Pentothal |
| Subject’s Response | Strictly “Yes” or “No” | Elaborate Verbal Answers |
+————————+————————————+———————————-+
Narco-Analysis: We administer a psychotropic drug—1 gram of Sodium Pentothal diluted in 1 liter of distilled water—to transition the subject into a subconscious “trance” state. If the drug dosage is slightly too high, the subject can slip into a coma or die; if it is too low, they remain conscious enough to fabricate stories. Because of this medical risk, Narco tests are never conducted in a lab—they are performed inside a hospital Operation Theatre (OT) with an Anesthetist, a Physician, a Psychologist, and a Videographer present.
Brain Fingerprinting (Brain Mapping): The subject and examiner sit in separate rooms. Sensors measure brain wave responses (EEG) when crime-related visuals or sounds are presented, verifying if crime details are stored in the subject’s memory.
Polygraph (Lie Detector): Conducted in a quiet lab room with only two people,the examiner and the subject.
9. Famous High-Profile Cases: Aarushi Talwar & Ajmal Kasab
Radhika: Have these psychological tests ever given conflicting or famous results?
Dr. Anita Evangeline: Yes:
The Aarushi Talwar Case: During Narco-analysis on Krishna (a subject in the 13-year-old Aarushi Talwar murder case), he gave multiple, contradictory statements under the drug’s influence—first claiming the murder weapon was in a flush tank, then a water tank, then thrown outside. Because police could not recover the weapon based on his statements, the scientific reliability of those statements was compromised, contributing to the ultimate lack of direct evidence in court.
Ajmal Kasab (26/11 Mumbai Attacks): Terrorist Ajmal Kasab voluntarily gave consent for both Polygraph and Narco tests. Guilty individuals who give consent often do so out of overconfidence, believing they can manipulate examiners or control their answers. However, under Narco-analysis in the OT, Kasab’s subconscious revelations provided vital investigative insights.
10. The Delhi Insulin Syringe Mystery & Police “Letter of Advice”
Radhika: How do police communicate their questions to the FSL?
Dr. Anita Evangeline: Police send a formal document called the Letter of Advice, listing specific questions about the evidence.
A great example of thorough evidence analysis involved a Telugu student found dead in Delhi. The student’s body was discovered rotting inside a locked room. Delhi police found no signs of struggle, trauma, or robbery, and considered closing it as a non-suspicious death. The grieving parents insisted their son was intelligent, calm, and had no enemies.
A special team from Telangana FSL visited the scene. While inspecting the room, our team spotted a tiny, discarded insulin syringe needle in the trash—something previous inspectors had overlooked. When we questioned the parents about it, they revealed for the first time that their son was diabetic and took insulin. Chemical analysis confirmed he had accidentally taken an insulin overdose, causing fatal hypoglycemia and low blood pressure while alone. A single needle solved the mystery.
11. Polygraph Mechanics: The 10-Question Structure & 3 Body Parameters
Radhika: How does a Polygraph machine actually detect a lie if there are no lights or buzzers?
Dr. Anita Evangeline: The test relies on the Psychosomatic Principle—the direct connection between mind and body. When you consciously lie, subconscious fear triggers involuntary bodily reactions.
We frame a 10-question test based on the case details:
4 Relevant Questions: Direct crime questions (“Did you stab X?”, “Do you know where the weapon is?”).
4 Irrelevant Questions: Known, non-threatening personal facts (“Is your name Radhika?”, “Is today Tuesday?”) to establish a baseline where the subject answers “Yes” calmly.
2 Probable / Comparative Questions: Control questions (“Have you ever lied in your life?”) designed to measure baseline physiological stress.
For all 10 questions, the subject must answer strictly “Yes” or “No”.
While they answer, sensors record three involuntary physiological parameters on a continuous computer graph (Polygram):
Respiration: Pneumograph tubes around the chest and abdomen track breathing rate, depth, and breath-holding.
Blood Pressure & Pulse: An arm cuff records heart rate spikes and blood pressure fluctuations.
Galvanic Skin Response (GSR): Finger electrodes measure micro-changes in sweat gland activity and skin conductance caused by anxiety.
12. Innocent vs. Guilty Behavior & The Warangal Bank Scam
Radhika: What if an innocent person is just terrified of taking the test, or a clever criminal tries to cheat the machine?
Dr. Anita Evangeline: That is a crucial question. An innocent person is nervous before questioning begins, but as we ask simple baseline questions, their physiological graph stabilizes and returns to normal. Once the test finishes and we tell them to relax, they visibly calm down. A guilty person, however, exhibits persistent, elevated stress spikes whenever relevant crime questions are asked. Even after we tell them the test is over, their anxiety remains high because they worry about the results.
To prevent suspects from using countermeasures (like holding their breath, swallowing, or anticipating questions), we run the 10 questions across 3 separate rounds, completely jumbling the order in rounds 2 and 3 so they cannot mentally prepare.
A classic case was the Warangal Co-operative Bank Scam: Customers began complaining that funds were disappearing via unauthorized debit card withdrawals. Police suspected internal staff, and brought the bank manager, cashier, and employees to our lab for polygraph testing. Tests proved the manager and cashier were completely innocent.
However, police had left out one young outsourcing employee because the manager trusted him implicitly with passwords. We insisted on testing him. On the polygraph, his graphs showed overwhelming deceptive criteria across all parameters. During post-test counseling, he broke down and confessed. He had stolen ₹2 lakhs to cover personal financial pressure after marriage. He led police to his backyard, where he had buried a half-burnt debit card wrapped in plastic under a guava tree. Police dug up the card, providing physical recovery that corroborated his polygraph confession.
13. The Vanasthalipuram 21-Day Infant Homicide
Radhika: Can you share another case where psychological testing exposed an unsuspected truth?
Dr. Anita Evangeline: One of the most heartbreaking cases in my 31-year career occurred in Vanasthalipuram. A poor laborer couple already had four daughters. When the wife gave birth to a fifth daughter, the husband was deeply disappointed, wanting a son. On the 21st day after birth (the barasala ceremony), the husband drank alcohol with fellow laborers, who mocked him, asking how he would ever afford dowries for five daughters.
In a drunken rage late that night, he decided to kill the infant. The mother tried to stop him, but he threatened to murder her and the other children. He forced the weeping mother to hold the baby while he used a heavy farm sickle (sikkel) to sever the 21-day-old infant into three parts. Before dawn, he scattered the infant’s head, trunk, and legs across different nearby streets.
The next morning, residents found a small baby skull on their doorstep, and a patrolling police car spotted a stray dog carrying a tiny leg in its mouth. Police and local residents assumed stray dogs had dragged the baby away and torn it apart. The father even filed a false missing-child police report blaming stray dogs.
However, when our forensic team examined the severed remains under microscopes, we noticed something vital: there were no jagged animal bite marks. Instead, the bone and tissue edges showed clean, smooth cuts from a sharp weapon.
Police brought both parents for polygraph testing. The traumatized mother broke down during post-test counseling and revealed the truth. When re-interrogated with specific questions, the father showed clear deceptive responses. He finally confessed and revealed where he had washed and hidden the sickle—inside the thatched roof of their hut. Lab tests matched the infant’s blood on the recovered sickle, convicting the father.
14. Legal Framework: Consent, Rights, & Career Advice
Radhika: Are polygraph or narco test results directly admissible in court to punish someone?
Dr. Anita Evangeline: No. Under the landmark Supreme Court ruling Selvi vs. State of Karnataka (2010), mandatory or forced psychological testing is unconstitutional. These tests were introduced to replace brutal third-degree police methods with scientific tools, but they require voluntary, free-will consent from the subject.
Furthermore, polygraph and narco results are treated as corroborative investigative aids, not primary substantive evidence. They provide a roadmap for police to uncover physical recoveries (like the hidden sickle or buried debit card), which are then admitted in court.
Radhika: What advice do you have for young students aspiring to join the field of forensic science?
Dr. Anita Evangeline: Forensic science is a deeply fulfilling and noble career. To succeed, you must possess unwavering integrity, scientific temper, and honesty. In our line of work, shortcuts or evidence tampering can destroy human lives and ruin your career one expert who edited a Narco CD was permanently dismissed from service.
Today, educational opportunities are expanding, with specialized M.Sc. programs and institutions like the National Forensic Sciences University. If you approach forensics with passion and truthfulness, you become an indispensable pillar of the justice system.
