For that reason he escaped being seen by a tall young Mexican whom he caught sight of lounging at the corner opposite the building that held Las Nuevas.  Ostensibly the fellow had merely stopped to light a cigarette, but while Starr watched him he struck three matches in succession, and immediately afterwards a shadow glided from the shelter of a plumber’s shop opposite, slipped down to the gate that was always barred, and disappeared.

Starr circled warily to the rear of the yard to see what chance there might be of getting over the wall unseen.  He did not know what good it would do him to get into the yard, but he hoped that he might be lucky enough to see any one who entered the back door, which would be the logical means of ingress.

He was standing back of the garage where he had found the cord tires, when the quiet of the night was split with the shrill, nerve-racking shriek of the fire whistle, four or five blocks away.  In spite of himself, he was startled with its suddenness, and he stood tensed and waiting for the dismal hoots that would tell what ward the fire was in.  One—­two—­three, croaked the siren like a giant hoot-owl calling in the night.

“Third ward—­down around the depot, probably,” he heard a voice say guardedly on the other side of the fence.  Another voice, more guarded even than the first, muttered a reply which Starr could not catch.  Neither voice was recognizable, and the sentence he heard was so obvious a remark as to be practically meaningless; probably a hundred persons in town had said “Third ward,” when the siren had tooted the number.

At any rate some one was there in the yard of Las Nuevas, and it would not be wise for Starr to attempt getting over the wall.  He waited therefore until he heard careful footsteps moving away; whereupon he himself stole quietly to the corner, thence down the side wall to the front of the building, so that he could look across the street to where the Mexican had revealed himself for a moment in the light of a distant street lamp.

If the Mexican had been on watch there, he had left his post.  In a minute Starr saw him hurrying down the unused side street, toward the angry glow that told where the fire had started.  Too much temptation, Starr interpreted the fellow’s desertion of his post; or else no more men were expected at Las Nuevas, and the outpost was no longer needed.  Taking it for granted that a meeting had been called here, Starr reasoned from that assumption.

He waited another minute or two, watching and listening.  There was nothing at the front to break the quiet or spoil the air of desertion that surrounds an empty office building at midnight.  He went cautiously to the rear corner and turned there to look back at the building, watchful for any stray beam of light or any movement.

The upper story was dark as the rest of the yard and building, and Starr could almost believe that he was on the wrong track entirely, and that nothing was going on here.  But he continued to stand there, loath to give up and go home with nothing accomplished.