Forensics leaps ahead even as labs struggle to keep pace

Modern investigative tools are transforming crime-solving in the country, but resource-strapped forensic science labs face challenges in meeting the rising demand.

Bengaluru: On August 1, all of Karnataka, especially the Janata Dal (Secular) strongholds, was glued to their TV sets as anticipation ran high in political circles. 

In a landmark judgement, Judge Santhosh Gajanan Bhat of the special court for elected representatives in Bengaluru convicted former MP Prajwal Revanna (35), the scion of the JD(S), in the first of four rape cases against him. 

The following day, Bhat pronounced a maximum life sentence — imprisonment for the remainder of the person’s natural life. The court, in its judgment, welcomed the Special Investigation Team (SIT) for “adopting and utilising the modern technology of scientific examination”, underscoring how crucial forensic evidence was in the high-profile rape case investigation.

It was a challenging task for the SIT, especially to establish that the person in the viral videos leaked in April 2024, depicting the survivors, was indeed Prajwal. For this, investigators referred to methodologies employed in Turkey and Japan to obtain a forensic confirmation. 

Investigators compared the physical characteristics of the body parts seen in the video — a mole on the left middle finger and a scar on the left hand — and concluded that they were Prajwal’s. Apart from this, investigators also relied on voice samples and DNA evidence, such as traces of semen on the survivor’s petticoat, to nail the accused.  

In another recent case from Andhra Pradesh, where 19 passengers were killed after a fire broke out in an AC sleeper bus in Kurnool, forensic teams studied vehicle construction defects, road conditions and the angle of impact. Meanwhile, the chemical team examined causes of fire spread, the diesel tank, explosives and other chemical evidence. 

Reports from these teams were instrumental in clarifying the exact cause of the accident.

“With coordination from DNA experts, continuous efforts were made to analyse and develop DNA profiles of all 19 deceased using advanced automated DNA extraction systems and STR-based DNA profiling technology. These profiles were matched with those of relatives. All reports were provided within 24 hours,” says G Pala Raju, Director, Andhra Pradesh Forensic Science Laboratory (APFSL).

As technology is evolving in India and worldwide, police investigators are increasingly turning to advanced forensic analysis — digital and cyber forensics, DNA analysis and genetic profiling, forensic toxicology and other methods — to strengthen chargesheets and secure convictions.

From the establishment of the world's first fingerprint bureau in 1897 in Kolkata to setting up high-tech labs with modern equipment and trained staff, forensic science has undergone significant evolution in the country. 

In recent years, forensic science has emerged as a critical tool in many investigations, particularly in high-profile cases. Following the July 11, 2006 blasts on suburban trains in Mumbai, forensic experts and commercial artists reconstructed the face of the unclaimed body that was left unidentified for over a month. The computer-generated sketch was prepared after forensic experts created a clay model of the deceased. 

Since only the upper torso of the body was recovered, with the rear portion of the skull and some part of the face mangled, doctors first performed a cosmetic surgery to replace missing facial tissues and bone. Then, commercial artist Dattatray Bapat prepared a clay model providing a three-dimensional glimpse of the victim's face. The man was later identified as Salim, one of the suspects. 

“Forensic investigation assumes great significance in cases involving circumstantial evidence and when there is a risk that eyewitnesses and other witnesses may turn hostile due to the accused's financial resources and influence,” says Rahul Machaiah, a Bengaluru-based advocate.  

“Forensic investigation is crucial to securing a conviction when there is a delay in reporting a crime, which could, in turn, raise suspicions about the victim's testimony, as there is scope for tutoring before lodging the complaint,” he says.

The chain of custody factor

To ensure conviction, the collection and handling of evidence are crucial. Chain of custody is the systematic process of collecting, handling, preserving, transporting and presenting physical and digital evidence from the crime scene to the court. 

“For evidence to be admissible in court, there has to be a documented chain showing where the evidence was collected, who handled it and how it was stored until it is presented in the court for trial. All of this must be done in front of independent witnesses (panchas). In case the seal of evidence needs to be opened, there needs to be a court order and the presence of panchas,” explains a senior Bengaluru police officer, who previously served in the Karnataka Criminal Investigation Department (CID). 

“If a mobile device seized from a crime scene is opened or tampered with without authorisation after being documented and sealed, it breaks the chain of custody. Forensic analysis can detect such unauthorised activity, potentially rendering the evidence inside the device inadmissible in court,” the officer says. 

Advocate Rahul Machaiah says a forensic expert's opinion is a "relevant fact" under Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 and the erstwhile Indian Evidence Act, 1872.  

“However, the opinion is not necessarily conclusive as the opinion is to be appreciated in the context of the other evidence, such as eyewitnesses' depositions, Investigating Officer's evidence, etc. The forensic opinion will lose its sanctity if the samples and devices aren't seized according to law, thereby vitiating the seizure or collection itself,” he explains. 

“Chain of custody is also vital in the context of digital evidence, as tampering with digital evidence in police custody is not uncommon. Hash functions are crucial to ensure that the digital evidence has not been tampered with after seizure. The new Bharatiya Sakshya Adhiniyam (Section 63 r/w the schedule) emphasises the generation of a hash value of digital records. While this is a good development, police officers, especially the head constables and ASIs investigating non-heinous cases, struggle with compliance as they lack adequate knowledge of digital forensics and the law of digital evidence.

"Forensic science is not infallible. False positives are not uncommon. As a result, the SC is right in repeatedly ruling that medical evidence and forensic evidence would not prevail over credible eyewitness statements when there is a conflict," he adds. 

The state of forensic science

According to the Press Information Bureau (PIB), as of 2024, there are seven Central Forensic Science Laboratories (CFSLs) in India: Bhopal (Madhya Pradesh), Chandigarh, Kamrup (Assam), Hyderabad (Telangana), Pune (Maharashtra), Delhi and Kolkata (West Bengal). There are also 32 State Forensic Science Laboratories (SFSLs) and 97 Regional Forensic Science Laboratories (RFSLs) across the country. 

There have been several modernisation methods like upgrading machinery and equipment at CFSLs,  including in the new disciplines of Forensics in Narcotic Drugs and Psychotropic Substances, Digital Forensics, DNA Forensic Analysis, Forensic Psychology; a state-of-the-art DNA analysis and R&D facility at CFSL, Chandigarh; National Cyber Forensic Laboratory (NCFL) at CFSL, Hyderabad; and the e-Forensics IT platform connecting 117 forensic laboratories, as per the PIB.

In the past year, the APFSL submitted 24,389 reports to the police department. Reports for DNA, NARCO, POCSO, murder and rape cases are delivered within three days. Forensic reports contributed to 78% of convictions in Andhra Pradesh, as per officials. 

The FSL in Gandhinagar, Gujarat, has become one of the most sought-after centres in India, offering critical forensic support in several high-profile cases. Its expertise came in handy in identifying passengers and others killed in the recent Air India plane crash in a short time. 

In Karnataka, due to the improved DNA testing units and an adequate workforce, the turnaround time for forensic analysis reports has been reduced to one month from the previous average of a year or more, according to reports. The state has also stationed mobile FSLs, along with highly-trained scene of crime (SOCO) officers, for evidence gathering. 

Many challenges 

However, FSLs nationwide are plagued by large vacancies, underutilised budgets and backlogs, leading to delays in investigations.  

For instance, despite having some of the country’s best infrastructure, Gandhinagar’s FSL faces a severe shortage of staff. Official sources in Gujarat said that the high demand for forensic services from various agencies, coupled with the prioritisation of high-profile cases, has led to delays in processing cases from local police.

The situation is similar in Tamil Nadu. Most labs in the state struggle with staff shortages and infrastructure constraints, resulting in delayed reports and prolonged investigation timelines. Sources said at least half of the posts in the labs, including that of forensic doctors, are lying vacant, which adds to the burden of the workforce who have to do the additional work. 

“If a work takes about 10 days with full strength, we now take twice as long to complete the exercise due to a staff shortage,” an official says. 

Advocate Rahul Machaiah says, “We need more FSLs in the state and better facilities, as forensic reports take very long to be submitted in court. These days, most of the crimes involve digital evidence (CCTV footage, phones, etc). Hence, delays in FSL reports can push back trials, by which time witnesses may forget crucial details and risk being discredited in court.” risk being discredited in court.” 

“Along with better forensic facilities, the government must ensure that cops handle evidence scrupulously and must prosecute police officers who fabricate or tamper with evidence. For instance, some FSL reports have proved that the seized substance was not a prohibited drug while the accused remained in jail under the NDPS Act. FSL reports in certain POCSO cases have revealed that the accused was not the father of the child delivered by the minor.”

The future of digital forensics 

With the advent of artificial intelligence (AI), technology is evolving, and so are cybercriminals. Cybercrimes now involve the use of AI, cryptocurrency, blockchain, deepfakes and other technologies, creating a growing need for modern digital forensic techniques. Since digital evidence will become key in securing convictions related to cybercrimes, forensic systems must now be capable of handling cryptocurrency wallets, AI-generated content, encrypted messengers, cloud storage, smartphones, advanced computers, and data from social media, officials say. 

In 2019, Karnataka police were the first to provide digital forensic tools to each cyber police station in the state, says a senior Bengaluru police officer specialised in cybercrime investigations. Till then, CID’s cyber lab in Bengaluru was the only facility for the entire state, he says.   

“Slowly, the stations were equipped with tools for cryptocurrency and social media analysis. Parallelly, the FSL was also equipped with modern tools and trained staff, leading to an analysis report of a smartphone in three months,” the officer explains. 

“But globally, digital forensics as a whole has gone down due to the improvement in security features by companies, which, from the point of view of an end user, is excellent. As a result, extracting data from seized digital devices has become more complicated. Some of the features may include encryption and the requirement to enter PINs and passwords when a device remains inactive for a specified period. Even the use of Virtual Private Networks (VPNs) has led to challenges in tracing the criminals,” says the officer. 

Despite technological advancements and the different paths, they follow, the core values of digital and traditional forensics remain the same. 

“There is a concept formulated by Dr Edmond Locard, a French criminologist. Locard's Exchange Principle states that every contact leaves a trace. Both traditional and digital forensic investigators follow this,” says the senior police officer. 

(With inputs from SNV Sudhir in Telangana, ETB Sivapriyan in Tamil Nadu, Arjun Raghunath in Kerala, Sumir Karmakar in Assam and Mrityunjay Bose in Maharashtra)