The arms had been straightened to the body to the elbows, and then crossed decorously on the breast.  Barrant walked round to the other side of the bed, knelt down by the edge of it, and examined the underneath part of the arm.  A single livid mark was imprinted upon it.

The inference was unmistakable.  The four upper marks were fingerprints, and the lower one a thumb mark.  Somebody had caught the dead man’s arm in such a strenuous grip that the livid impression had remained after death.

The discovery was significant enough, but Barrant was not at that moment prepared to say how much it portended.  It seemed certain that the marks had not been made by Robert Turold himself.  Their position suggested a left-hand clutch, though only a finger-print expert could definitely determine that point.  Even if they were not, it was too far-fetched a supposition to imagine a man gripping his own arm hard enough to bruise it.

The relative weight of this discovery was, in Barrant’s mind, weakened by the fact that the marks might have been caused by the persons who had carried the body from the next room.  Nevertheless, the marks must be regarded as infirmative testimony, however slight, of the fallibility of the circumstantial deductions which had been made from the discovery of the body in a locked room, with windows which could not be reached from the outside.

The presumption of suicide rested on the theory that the circumstances excluded any other hypothesis.  But Barrant reflected that he did not know enough about the case to accept that assumption as warranted by the facts.  The one certainty was that the study could not have been reached from the outside.  Barrant had noted the back windows before entering the house; his subsequent interior examination had strengthened his conviction that they were inaccessible.  Underneath the study windows there was only the narrowest ledge of rock between that side of the house and the edge of the cliffs.  A descent from the windows with a rope was hazardously possible, but ascent and entrance by that means was out of the question.

On the other hand, the theory of interior inaccessibility had a flaw in it, due to the presence of five different people in the room before the police arrived.  Their actions and motives would have to be most carefully weighed and sifted before the implication of the discovery of the finger-marks could be determined.

The rather breathless entrance of Inspector Dawfield put an end to Barrant’s reflections.  He explained that Sergeant Pengowan, in his anxiety to maintain the correctness of his official report, had taken him to various breakneck positions at the back of the house and along the cliffs in order to demonstrate the impossibility of anybody entering Robert Turold’s rooms from outside.  The sergeant was at that moment engaged in a room downstairs drawing up his reasons for that belief.  “A kind of confirmatory report,” Dawfield explained.  “He fears that his reputation is at stake.”