DNA: Is role of `former principal` suspicious in Kolkata doctor rape-murder?

Even after eight days have passed since the rape and murder of a lady doctor in Kolkata, the list of allegations and questions is not ending. A new CCTV footage has surfaced of the seminar hall where brutality took place with a female trainee doctor in Kolkata. When CBI intensified its investigation in the whole matter, the former principal of RG Kar College came under the scanner of many questions.