a quarter to eight
Besides , Pestryakov , the student , was seen at the gate by both the porters and a woman as he went in . He was walking with three friends , who left him only at the gate , and he asked the porters to direct him , in the presence of the friends . Now , would he have asked his way if he had been going with such an object ? As for Koch , he spent half an hour at the silversmith 's below , before he went up to the old woman and he left him at exactly a quarter to eight . Now just consider ... '' `` But excuse me , how do you explain this contradiction ? They state themselves that they knocked and the door was locked ; yet three minutes later when they went up with the porter , it turned out the door was unfastened . '' `` That 's just it ; the murderer must have been there and bolted himself in ; and they 'd have caught him for a certainty if Koch had not been an ass and gone to look for the porter too .