was gone. Yes, Shirley was her daughter. How old? Seven and ahalf. How long ago was this? Fifteen minutes, maybe. She hadn't beenworried at first; she'd walked up and down, calling the girl's name,but hadn't gotten any answer. Then she saw the policeman, and ...and--

  And she broke down into tears again.

  It was the same thing that had happened a few days before. I hadalready ordered extra men put on the Riverside and Central Parkdetails, but a cop can't be everywhere at once.

  "I've got the rest of the boys beating the brush between here and theriver," Officer Ramirez said. "She might have gone down one of thepaths on the other side of the wall."

  "She wouldn't go too near the river," the woman sobbed. "I just knowshe wouldn't." She sounded as though she were trying to convinceherself and failing miserably.

  Nobody said anything about Nestor; the poor woman was bad enough offwithout adding more horror to the pictures she was conjuring up in hermind.

  "We'll find her," I said soothingly, "don't you worry about that.You're pretty upset. We'll have the police doctor look you over andmaybe give you a tranquilizer or something to make you feel better."No point in telling her that the doctor might be needed for a moreserious case. "Keep an eye on her till the doctor comes, Ramirez.Meanwhile, we'll look around for the little girl."

  * * * * *

  I walked over to the wall and looked down. I could see uniformedpolice walking around, covering the ground carefully.

  Riverside Park runs along the eastern edge of Manhattan Island,between Riverside Drive and the Hudson River, from 72nd Street on thesouth to 129th Street on the north. In the area where we were, thereis a flat, level, grassy area about a block wide, where there arewalks and benches to sit on. The eastern boundary of this area ismarked by a retaining wall that runs parallel with the river. Beyondthe wall, the ground slopes down sharply to the Hudson River, goingunder the elevated East Side Highway which carries express traffic upand down the island. The retaining wall is cut through at intervals,and winding steps go down the steep slope. There are bushes and treesall over down there.

  I thought for a minute, then said, "Suppose it was Nestor. How did heget her away? It's a cinch he didn't just scoop her up in broaddaylight and go trotting off with her under his arm."

  "Precisely what I was thinking," the Duke agreed. "There was no screamor disturbance of that kind. Could he have lured her away, do youthink?"

  "Possible, but not likely. Little girls in New York are warned aboutthat sort of thing from the time they're in diapers. If she were fiveyears old, it might be more probable, but little girls who areapproaching eight are pretty wise little girls."

  "It follows, then, that she went somewhere of her own accord and hefollowed her. D'you agree?"

  "That sounds most reasonable," I said. "The next question is: Where?"

  "Yes. And why didn't she tell her mother where she was going?"

  I gave him a sour grin. "Elementary, my dear Duke. Because her motherhad forbidden her to go there. And, from the way she was talking, Igather the mother had expressly directed her to stay away from theriver." I looked back over the retaining wall again. "But it justdoesn't sound right, does it? Surely someone would have seen any sortof attack like that. Of course, it's possible that she _did_ fall inthe river, and that this case doesn't have anything to do with Nestorat all, but--"

  "It doesn't feel that way to me, either," said the Duke.

  "Let's go talk to the mother again," I said. "There are plenty of mendown there now; they don't need us."

  The woman, Mrs. Ebbermann, had calmed down a little. The policesurgeon had given her a tranquilizer with a hypogun, Officer Ramirezwas getting everything down in his notebook, and his belt recorder wasrunning.

  "No," she was saying, "I'm sure she didn't go home. That's the firstplace I looked after she didn't answer when I called. We live down theblock there. I thought she might have gone home to go to the bathroomor something--but I'm sure she would have told me." She choked alittle. "Oh, Shirley, baby! Where are you? Where _are_ you?"

  I started to ask her a question, but she suddenly said: "Shirley,baby, next time, I promise, you can bring your water gun with you tothe park, if you'll just come back to Mommie now! Please, Shirley,baby! Please!"

  I glanced at the Duke. He gave me the same sort of look.

  "What was that about a water gun, Mrs. Ebbermann?" I asked casually.

  "Oh, she wanted to bring her water gun with her, poor baby. But I madeher leave it at home--I was afraid she might squirt people with it.But I shouldn't have done that! She's a good girl! She wouldn't squirtanybody!"

  "Sure not, Mrs. Ebbermann. Does Shirley have a key to your apartment?"

  "Yes. I gave her her own key, a pretty one, with her initials on it,for her seventh birthday, so she wouldn't have to push the buzzer whenshe came home from school."

  "Where's your husband?" I asked taking a look at Ramirez' notebook toget her address.

  "Shirley's father? Somewhere in Boston. We've been separated for twoyears. But I wish he were here!"

  "Would you give me the key to your apartment, Mrs. Ebbermann? We'dlike to take a look around."

  She gave me a key. "But she's not there. I told you, that's the firstplace I looked."

  "I know," I said. "We just want to look around. We won't disturbanything."

  Then His Grace and I got out of there as fast as we could.

  * * * * *

  I keyed open the front door of the apartment building, and we wentinside. Neither of us said anything. There was no need to. We knewwhat must have happened, we could see it unfolding as plainly as ifwe'd watched it happen.

  Nestor had seen Shirley sneak off from her mother and had followedher. In order to get into the building, he must have come right inwith her, right behind her when she unlocked the outer door. Thenwhat?

  The chances were a billion to one against his ever having been in thebuilding before, so it stood to reason that all he would have beendoing is watching for an opportunity and--the right place.

  The foyer itself? No. Too much chance of being seen. The basement?Unlikely. He must have followed her into the elevator, and she wouldhave pushed the button for the seventh floor, where her apartment was,so there wouldn't be much likelihood of his getting a chance to seethe basement. Besides, there was a chance that he might run into thejanitor.

  * * * * *

  The Duke and I went into the old-fashioned self-service elevator, andI pushed number seven. The doors slid shut, and the car started up.The roof? No. Too much danger of being seen from other buildingshigher than this one.

  Where, then? I looked at the control panel of the elevator. The buttonfor the basement was controlled by a key; only the employees wereallowed in the basement, so that place was ruled out absolutely.

  I began to get the feeling that we were on a wild goose chase, afterall. "What do you think?" I asked His Grace.

  "I can't imagine where he might have taken her. We may have to searchthe whole building."

  The car stopped at the seventh door, and we stepped out as the doorsslid open. The hallways stretched to either side, but there were noapparent hiding places. I went over to the stairwell, which was rightnext to the elevator shaft and looked up and down. No place there,either.

  Then it hit me.

  Again, I could see Nestor, like a scene unfolding on a TV drama, stillfollowing little Shirley. Had he spoken to her in the elevator? Maybe.Maybe not. He was still undecided, so he followed her to the door ofher apartment. Wait--very likely, he _had_ made friends with her onthe elevator. He saw her push button seven--

  _Well, well! Do you live on the seventh floor?_

  _Yes, I do._

  _Then we're neighbors. I live on the seventh, too. I just moved in. Doyou live with your mommie and daddy?_

  _Just my mommie. My daddy doesn't live with us anymore._

  And, since he knew that mommie was in the park,
he could guess thatthe apartment was empty.

  All that went through my mind like a bolt of lightning. I said: "Theapartment! Come on!"

  The Duke, looking a little puzzled, followed me to the door of 706. Iput my ear against the door and listened. Nothing. Then I eased thekey in and flung the door open.

  No one in the living room. I raced for the bedroom. No one in there,either, but the clothes closet door was shut.

  When I opened it, we saw a small, dark-haired girl lying naked andunconscious on the floor.

  Then there were noises from the front room. The sound of a dooropening and closing, and the clatter of hurrying footsteps