That discovery sent me groping hurriedly backward into the darkened hallway. By the time the door opened I had felt my way to a second flight of steps which obviously led to the basement. I could hear the voice of the man known as The Doc, for the three men were now advancing, and advancing none too quietly, into their musty-aired harborage. But my own flight down those basement stairs was quiet enough, for I realized now the expediency of slipping away and putting in a call for help. It was only after a good deal of groping about, however, that I was able to reach the door opening on the basement-area, directly under the street-steps. A huge brass key, fortunately, stood in place there. So as I passed out I took the trouble to relock that door after me and pocket the key. In five minutes I had found a side-street grocery-store with a sufficiently sequestered telephone. And by means of this telephone I promptly called up Headquarters and asked for Lieutenant Belton. He listened to what I had to say with much more interest than I had anticipated. "Witter," he called back over the wire, "I believe you've stumbled across something big." "Then supposing you stumble over here after it," was my prompt suggestion. But Belton wasn't to be stampeded into the over-hasty action of the amateur. "If that isn't that bunch Headquarters has been wanting to interview for the last three months, I miss my one best bet. But in this business, Witter, you've got to _know_. So I'll slip over to the Bureau and look up mugs and records. If that faint-spiller is Bab Nadeau, _alias_ Car-Step Sadie, there's no doubt about your man being Crotty." "She _is_ Car-Step Sadie," I told him. "Then we'll be out there with bells on," he calmly announced. "But what do you expect me to do, in the meantime?" I somewhat peevishly demanded. "Just keep 'em guessing," he tranquilly retorted, "keep 'em guessing until we amble over there and take 'em off your hands!" That was easy enough to say, I remembered as I made my way back to Crotty's broken-faced abode, but the problem of holding that unsavory trio in subjection didn't impress me as an over-trivial one. Yet I went back with a new fortitude stiffening my backbone, for I knew that whatever might happen that night, I now had the Law on my side. That casual little flicker of confidence, however, was not destined to sustain me for long. A new complication suddenly confronted me. For as I guardedly approached the house from which I'd sent Bab Nadeau scampering off into the night I noticed the Nile-green car already drawn up close beside the curb. And this car, I further noticed, was empty. So it was with a perceptibly quickened pulse that I sidled down into the unclean area, unearthed my brass key, and let myself silently into the unlighted basement. Then I just as quietly piloted my way in through the darkness, found the stairway, and ascended to the ground floor.