 He also selected a meeting place in the centre of Hogg's Market in Calcutta at a very busy time of the day, so that he could pass by the responder without being detected.Byomkesh guessed that the advertiser would probably want to slip something into the responder's pocket, perhaps some instructions, and would want to accomplish this without being detected.Ajit argued that all of this was circumstantial evidence at best and challenged Byomkesh to prove it, a challenge that Byomkesh heartily accepted.