The Forensic Science Laboratory (FSL) Wednesday started using the layered voice analysis (LVA) programme, said to help detect lies and screen suspects. The technology is used by the FBI in the United States, and the FSL has procured the software from Mossad, Israel’s national intelligence agency.
The LVA, officials say, relies on voice frequency to ascertain whether a person is lying. The software samples the suspect’s voice to assess his “emotional state”, officials said, adding that it can “help investigators during questioning”.
When the technology was introduced in the West several decades ago, it was met with criticism, with several researchers in the US concluding that LVA was not a credible lie detection method.
While for earlier lie detection methods, like a polygraph test, FSL had to procure the permission of court, the LVA would apparently not need court intervention since it is “non-intrusive,” officials said.
“LVA relies on variations in voice and does not need wires or sensors attached to the body of a suspect. The voice sample can be taken online or offline. Even voice recorded earlier can be analysed,” FSL director Deepa Verma said. While earlier lie detection methods would take days or months, the new software is expected to churn out results “within minutes”, which can be analysed by experts from the forensic psychology division.
Senior FSL officials have been waiting for a year to procure the LVA programme, and started incorporating it in their work from Wednesday. An expert from Israel is expected to join the FSL and train them in interpreting data.
“Earlier, we used to rely on polygraph tests for lie detection. But with the LVA, we would be able to analyse the voice stress of the subject and ascertain with 96% accuracy whether the person is lying. We can also use this technology to ascertain the number of speakers and differentiate between them,” Verma said.
Asked about research finding flaws with the technique, Verma said, “Even polygraph tests and other forms of lie detection are not 100% accurate. Science and research have to evolve and this technology is the most accurate of all lie detection tests.”
Crime scene management in-charge Sanjeev Gupta said they can provide the technology to police during the stage of questioning.
“We will write to Delhi Police about the technology to record the suspects’ audio clips during questioning and help them ascertain if the suspect is lying. We can also effectively use this in terrorist interrogations,” Gupta said.