The cross-examination of Dr R.K. Sharma, the forensic expert called by the defence in the Aarushi-Hemraj trial, entered its third day on Thursday. The prosecution has spent much of this time trying to suggest that the former head of forensic science at AIIMS is a man of dubious integrity, rather than challenge the science behind his report.
Being tried for the 2008 murders of their daughter and their servant, Dr Rajesh and Nupur Talwar had sought Dr Sharma's services as an experienced independent consultant. Dr Sharma's report is based on material on record, such as the post-portem report and an inspection of the purported murder weapon, a golf club.
He had concluded that the golf club could not have been the weapon that caused the fatal line fractures (the kind of fracture you see as a coconut is split open) that were found on Aarushi and Hemraj. He has also testified that a scalpel would not have been able to inflict the wounds to the necks of the victims. Their throats were slit with a much larger weapon, Dr Sharma has said.
A scalpel would most likely break if someone tried to use it to cause the kind of deep wounds that were found on the victims, Dr Sharma has said, because not only is the carotid artery a tough pipe to cut, there are cartilages in the neck region that are hard to cut through.
Macabre anatomy lessons such as these have become a daily feature of the trial, but when the science is tough to question, there is another route: question the character of the witness.
Dr Sharma was thus asked why he paid just Rs 2,200 rent for his Connaught Place office (it is actually more like a workspace, according to defence counsel, Tanveer Ahmed Mir). Dr Sharma runs an outfit called Global Medico-Legal Consultancy from those premises, and the CBI counsel pointed out that his website says: "Lawyers can have our services for better interpretation of scientific evidence against or for them".
The implication, of course, is that Dr Sharma writes whatever his clients ask him to. The phrase "better interpretation", is, of course, open to interpretation. We will hear more about it on Friday.