Noiselessly they went up the street. It would be impossible for the sniper to see them unless he bent out over the edge of the roof from which he was firing.
While they were advancing another shot was fired from the same roof. Watching the direction of the flash, Darrin was able to guess the direction of the man or men at whom the Mexican was firing.
"Some of our sharpshooters must still be posted on roofs," Dave whispered over his shoulder to Riley.
"I know one man who won't be doing much more on a roof, if I can get a sight of him for three seconds," gruffly answered Riley.
Then they stopped in front of the house in question.
"You slip across to the doorway opposite, and watch for your man," whispered Darrin. "I'll remain here and get any one who may attempt to run out of the house after you open fire."
Slipping across the street, Riley waited.
Scanning the house, from the roof of which the firing had proceeded, his drawn revolver in his hand, Dave made a quick discovery.
"Why, this is the very door from which I saw Cosetta peering out yesterday!" thought the young ensign. "I wonder if this is his home in Vera Cruz. I'll make a point of reporting this to Trent as soon as we return."
And then Dave heard a voice just inside the door say, in Spanish: