"I can't say," admitted Darrel thoughtfully; "but of one thing I am certain: that the Blue Mummy is the clue to the whole mystery. What about Captain Manuel?"
"Why do you mention him?" asked Torry abruptly.
"Well," said Frank slowly, "it seems to me that the double tragedy has to do with Peru. Everywhere we turn we are met by Peru. In the first place, the mummy is a tomb image from the sepulchre of some Inca of Peru. In the second, the knife discovered was a Spanish-American bowie, which could only have come from the New World. In the third, Grent's wife and adopted child are Spanish ladies from Lima. Finally, Captain Manuel is from Peru, and is the confidential friend of the dead man. What do you make of all this?"
"That Grent was murdered by Manuel?" sneered Torry.
"No; but that we must look in South America--in Peru--in Lima for the motive of the crime. Grent was there many years ago; he brought home a Spanish wife; so who knows but what he might have made some enemies there who swore to kill him, and accomplished the tragedy of the other night."
"That might explain Grent's death," said Torry, nursing his chin in his hand, "but it does not reveal why this unknown woman should have been killed. Yet I am sure that the same motive will account for both deaths. Oh!" cried the detective, in despair, "If I could only find out that motive."
"Question Donna Inez," suggested Darrel. "She, if anyone, will explain the reason."
"Why so?"
"Because if my theory is correct she may remember if her husband made enemies in Peru."
"Peru! Peru! You have that Peru on the brain. No," said Torry, "I may see Donna Inez later, but first I intend to search the rooms of Grent."