'You understood? Why he killed him?' She was white to the lips. Gian Giacomo was leaning forward across the table, his face eager. She uttered a fretful laugh. 'He killed him because he was my friend, mine and my brother's, the chief of all our friends.'

Barbaresco shook his great head. 'He killed him because this Spigno whom we all trusted so completely was a spy of Theodore's.'

'What?'

Her world reeled about her; her senses battled in a mist. The thick, droning voice of Barbaresco came to deepen her confusion.

'It is all so simple; so very clear. The facts that Spigno was dressed as we found him and in the attic where we had imprisoned Bellarion should in themselves have explained everything. How came he there? Bellarion was all but convicted of being an agent of Theodore's. But for Spigno we should have dealt with him out of hand. Then at dead of night Spigno went to liberate him, and by that very act convicted himself in Bellarion's eyes. And for that Bellarion stabbed him. The only flaw is how one agent of Theodore's should have come to be under such a misapprehension about the other. Saving that the thing would have been clear at once.'

'That I can explain,' said Valeria breathlessly, 'if you have sound proof of Spigno's guilt, if it is not all based on rash assumption.'

'Assumption!' laughed Casella, and he took up the tale. 'That night, when we determined upon flight, we first repaired, because of our suspicions, to Spigno's lodging. We found there a letter addressed superscribed to Theodore, to be delivered in the event of Spigno's death or disappearance. Within it we found a list of our names and of the part which each of us had had in the plot to kill the Regent, and the terms of that letter made it more than clear that throughout Spigno had been Theodore's agent for the destruction of the Marquis here.'

'That letter,' said Barbaresco, 'was a safeguard the scoundrel had prepared in the event of discovery. The threat of its despatch to Theodore would have been used to compel us to hold our hands. Oh, a subtle villain, your best and most loyal friend Count Spigno, and but for Bellarion ...' He spread his hands and laughed.

Then Casella interposed.

'You said, madonna, that you could supply the link that's missing in our chain.'