What inference was to be drawn from that?
Sisily knew that they were kept in the clock-case, and pointed out the hiding place to her lover.

In a struggle for their possession Robert Turold was shot down, or he might have been shot first and staggered to the clock afterwards to see if they had been stolen.

Either supposition accounted for the fallen clock, and fitted in with nearly all the known facts of the murder.
Nearly all, but not all! In face of Mrs.Brierly's disclosure it seemed a condition precedent to the elucidation of the mystery to substitute Charles Turold for Thalassa as the person whose undisciplined love for Sisily had led him to shoot her father to shield her name.

Nor was it incredible to suppose that he had remained in Cornwall to cover her flight in the hope of diverting suspicion from her.

But the loose end in the theory was Thalassa's share in that night's events, and his dogged silence since under strong suspicion.
Thalassa knew more than he had yet revealed, but what did he know?
What was his share in the business?
It was difficult to say.