Kolkata, Nov 27 : The Central Bureau of Investigation (CBI) officials investigating the ghastly rape and murder of a junior doctor of R.G. Kar Medical College & Hospital in Kolkata in August are focusing heavily on the lapses in the post-mortem report of the victim's body to establish the theory of tampering with the evidence in the case.

CBI has collected reports of other post-mortems done on the day the autopsy of R.G. Kar victim's body was done.

Sources said that the investigating officials have sent all these autopsy reports, including the one of the victim, to forensic experts. The motive is to identify the qualitative difference between the autopsy report of the victim and that of others done on the same day.

At the same time, sources added, the investigating officials, through the process of interrogations of persons concerned, are also trying to figure out what prompted the hospital authorities to conduct the autopsy of the victim after sunset breaching the general protocol.

The other lapses in the autopsy process that the investigating officials are concentrating on are the unusually short period in which the post-mortem process was concluded and the poor quality of the video recording of the autopsy process done in an unusually dim light.

Sources said that there are two aspects in the investigation, the first being the actual 'rape and murder crime' and the second being the 'tampering and altering of evidence'.

While biological evidence is the base of establishing conviction in the 'rape and murder crime', circumstantial evidence is the base of the 'tampering and altering of evidence' aspect.

Now, sources added, based on the biological evidence available the investigating officials have identified civic volunteer Sanjay Roy as the 'sole prime accused' in the rape and murder crime in its first charge sheet.

Now, circumstantial evidence will be the key to establishing the offence of 'tampering and altering of evidence' aspect, where the two main accused so far are the former and controversial principal of R.G. Kar Sandip Ghosh and the former SHO of Tala Police station Abhijit Mondal..

/IANS