There was, additionally, the motive of self-interest, awakened to the lamentable fact that she had no claim on her father beyond what generosity might dictate.

In short, Barrant believed the motive for the murder to be a mixed one, as human motives generally are.

At that stage of his reasoning he did not ask himself whether worldly greed was likely to enter into the composition of a girl like Sisily.
This reconstruction of the crime pointed to an accomplice, and that accomplice must have been the man-servant.

Nobody but Thalassa could have let the girl into the house; and he could have dropped the key in the room after the door was broken open.

That theory not only presupposed strong devotion on Thalassa's part for a girl he had known from childhood, which was a theory reasonable of belief, but it also suggested that he bore a deep grudge against his master on his own account, sufficient to cause him to refrain from doing anything to prevent the accomplishment of the murder, and to risk his own skin afterwards to shield the girl from the consequences.