At the same moment a door opened and Gibelin appeared.  He was rather fat, with small, piercing eyes and a reddish mustache.  His voice was harsh, his manners brusque, but there was no denying his intelligence.  In a spirit of conciliation he began to give M. Pougeot some details of the case, whereupon the latter said stiffly:  “Excuse me, sir, I need no assistance from you in making this investigation.  Come, doctor!  In the field of his jurisdiction a commissary of police is supreme, taking precedence even over headquarters men.”  So Gibelin could only withdraw, muttering his resentment, while Pougeot proceeded with his duties.

In general plan the Ansonia was in the form of a large E, the main part of the second floor, where the tragedy took place, being occupied by public dining rooms, but the two wings, in accordance with Parisian custom, containing a number of private rooms where delicious meals might be had with discreet attendance by those who wished to dine alone.  In each of the wings were seven of these private rooms, all opening on a dark-red passageway lighted by soft electric lamps.  It was in one of the west wing private rooms that the crime had been committed, and as the commissary reached the wing the waiters’ awe-struck looks showed him plainly enough which was the room—­there, on the right, the second from the end, where the patient policeman was standing guard.

M. Pougeot paused at the turn of the corridor to ask some question, but he was interrupted by a burst of singing on the left, a roaring chorus of hilarity.

“It’s a banquet party,” explained the doctor, “a lot of Americans.  They don’t know what has happened.”

“Hah!” reflected the other.  “Just across the corridor, too!”

Then, briefly, the commissary heard what the witnesses had to tell him about the crime.  It had been discovered half an hour before, more precisely at ten minutes to nine, by a waiter Joseph, who was serving a couple in Number Six, a dark-complexioned man and a strikingly handsome woman.  They had arrived at a quarter before eight and the meal had begun at once.  Oddly enough, after the soup, the gentleman told the waiter not to bring the next course until he rang, at the same time slipping into his hand a ten-franc piece.  Whereupon Joseph had nodded his understanding—­he had seen impatient lovers before, although they usually restrained their ardor until after the fish; still, ma foi, this was a woman to make a man lose his head, and the night was to be a jolly one—­how those young American devils were singing!... so vive l’amour and vive la jeunesse! With which simple philosophy and a twinkle of satisfaction Joseph had tucked away his gold piece—­and waited.

Ten minutes!  Fifteen minutes!  An unconscionably long time when you have a delicious sole a la Regence getting cold on your hands.  Joseph knocked discreetly, then again after a decent pause, and finally, weary of waiting, he opened the door with an official cough of warning and stepped inside the room.  A moment later he started back, his eyes fixed with horror.