The Aarushi-Hemraj murder trial throws up a larger issue each hearing, and Tuesday was no different.
The integrity of the chain of custody of any piece of evidence is widely understood to be sacrosanct. But is this understanding wide enough to cover our investigating agencies?
On the evidence of Tuesday, it isn't. Deepak Tanwar, the Central Forensic Science Laboratory (CFSL) scientist, who was being cross examined, told the court that he had not seen the alleged murder weapon - a golf club from a set seized from the Talwars - after 13 August 2010. The CFSL had custody of the clubs till then, and submitted drawings and reports on the clubs: Their physical dimensions and how they matched the injuries; the amount of dirt on them, and so on.
Once this exercise was complete, the clubs were sealed and sent back to the CBI.
So how is it that the Talwars' driver, Umesh, supposedly identified the murder weapon from the set of 12 in the office of the investigating officer A.G.L. Kaul, on 2 September - three weeks after they were sealed by the CFSL?
Common sense tells you that this is impossible unless the seal on the evidence were broken. What is worrying is that all of this was happening in the office of the investigating officer, and that it is somehow acceptable?
Kaul hasn't exactly been the model of propriety in this investigation. He is the man who would use the macabre e-mail address 'email@example.com' in order to send official communication to the Talwars.
The CBI denied such an address was used by one of its officers, but foolishly submitted the e-mails as part of the evidence in the case to every court involved -including the Supreme Court.
But the larger issue here is less about the conduct of an individual officer, and more about the system that allows him to break seals on crucial pieces of evidence - in this case the purported murder weapon - and create e-mail addresses in order to conduct juvenile psy ops experiments.
Speaking of juvenile experiments, Kanwar's cross-examination had all the material necessary. He was one of the "scientists" who discovered that two men could carry a body wrapped in a bed sheet up one flight of stairs, after an elaborate crime scene re-enactment.
Kaul directed each step in this experiment, but the CFSL scientist admitted that an important instruction wasn't followed. The 'dummy test' conducted on the Talwars' terrace to see if the bloody drag marks found were indeed the result of Hemraj’s body being hauled across the terrace floor, were done with a constable (playing a corpse) wrapped in a sheet.
But Kaul had asked for a test without sheet as well. Kanwar admitted that the sans sheet experiment wasn't carried out.
Hemraj had contusions and abrasions around his elbows. Something that calls into question whether he was wrapped in a sheet when dragged.
In response to a closing question to the effect that this wasn't a 'dummy test' as much as it was a test conducted by dummies, the witness said that the science involved was impeccable.
P.S. Kanwar's senior in the CFSL, principal scientific officer Rajinder Singh, recently admitted to the court that he did not know whether the density of blood and a calibrated solution of water and Shalimar paint might be different.
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Avirook Sen has been a journalist and writer for over 20 years. A former resident editor of Hindustan Times (Mumbai) and editor of Mid-Day, he has written with passion and insight on subjects as varied as sport and terrorism for top publications across the world. His first book, Looking for America, was published in 2010 to enthusiastic reviews. You can write to him at firstname.lastname@example.org