You are right. This is a very well planned and executed murder. There are strong indicators to believe actual hand behind these murders is an educated man. If Krishna or any other servant had committed these murders, they would not have stayed in the locality. It is a common sense - there was no need for these people to stay in the places knowing that they will be caught. Even after initial questioning and prior to their arrest they continued to stay in the place they are staying. Rajesh Talwar's behaviour is very peculiar. If the news has to believed. Initial refusal of Rajesh Talwar to identiy Hemaraj speak volumes. Probably it was the guilt that made him to behave that way. How did they accept the PM report that had chronological error. It is hard to believe, Talwars are not involved.
