about
seven o'clock
The police , no doubt , would value an expert opinion . You _ must _ be here within ten minutes . '' The arrival of a couple of constables frustrated whatever object Dr. Simons had had in detaining Mr. Rohscheimer , but the doctor lingered on , evidently awaiting whoever he had spoken to on the telephone . The police ascertained from Rohscheimer that he had held an interest in the `` Douglas Graham '' business , that this business was of an usurious character , that the dead man 's real name was Paul Gottschalk , and that he , Rohscheimer , found the outer door fastened when he arrived at about seven o'clock , opened it with a key which he held , and saw Gottschalk as they saw him now . The office was in darkness . Apparently , valuables had been taken from the safe -- which was open . The staff usually left at six .