had no intention of murdering her father.  She knocked, and was perhaps admitted by Thalassa, and went up to her father’s room.  What happened during that interview?  We do not know, but we are told that Robert Turold was a man of harsh, unyielding disposition, the slave of his single idea, which was the acquisition of a lost title.  Such a man was not likely to be moved by pleading or threats.  We must imagine a long and angry scene, culminating in the daughter snatching up her father’s revolver and shooting him.”

“Thalassa told Pengowan that Robert Turold kept the revolver in the drawer of his writing table,” Dawfield remarked.

“I have read Pengowan’s report,” returned Barrant impatiently, “and I am assuming that Robert Turold’s daughter knew where it was kept.  This is a purely constructive theory of her guilt, and we have to assume many things.  We must further assume that when she left the room she locked the door behind her and brought away the key in order to suggest suicide.  When she got downstairs she told Thalassa the truth, and begged him to shield her.  He promised to do so, and when the door of the study was broken open he took an opportunity to drop the key on the floor, in order to suggest the idea that Robert Turold had locked himself in his room before shooting himself, and that the key was jolted out of the lock when the door was burst in.  It was an infernally clever thing to do.  That’s the case against the girl, Dawfield.  What do you think of it?”

“It sounds convincing enough.”

“It would sound more convincing to me if it was entirely consistent with the other facts of the case.  Have you those sheets of unfinished writing which were found in Robert Turold’s study?”

Dawfield produced two sheets of foolscap from his desk.  Barrant laid them on the table, and examined them with a magnifying glass.

“It is certain that Robert Turold did not put down his pen voluntarily,” he said.  “He stopped involuntarily, in the midst of a word.  That suggests great surprise or sudden shock.  The letter ‘e’ in the word ‘clear’ terminates in a sprawling dash and a jab from the nib which has almost pierced the paper.  Could the unexpected appearance of his daughter have startled him in that fashion?  It rather suggests that somebody sprang on him unawares, surprising him so much that he almost stuck the pen through the paper.”

“Might not that have been his daughter?”

“Women scratch like cats when they use violence, but they do not spring like tigers.  I have been examining those marks on Robert Turold’s arm again, and I have come to the conclusion that they were made by somebody in a violent passion.”

“I have the photographs here,” said Dawfield, rummaging in a drawer.  “They do not help us at all.  There are no finger-prints—­nothing but blurs.”

Barrant glanced at the photographs and pushed them aside.

“I have been thinking a lot about those marks,” he said.  “They strike me as a very important clue.  I have been examining them very closely, and discovered the faint impression of finger-nails in the marks left by the first and second fingers.  That suggests that the owner of the hand was in a state of ferocity and tightened nerves.”