I WONDERED IF YOU'D BE QUESTIONING ME," THE GREAT MERLINI said as he opened the door at 13½ Washington Square North and admitted a scowling Inspector Gavigan and an even glummer Lieutenant Malloy. Merlini indicated a headline in the newspaper he had been reading:

PHANTOM GUNMAN SHOOTS

UNIDENTIFIED MAN

$30,000 in Cash Found on Corpse

"A man gets killed at dusk last evening just across the street in the park—a hundred feet or so from my front door. Scores of people there, as usual, and one man actually saw the victim as he fell. Yet no one saw the murderer or heard the shot. I'm a magician. So I suspected you might suspect me."

Gavigan sat down wearily. "Have you," he asked, "ever been in Hillsdale, Oklahoma?"

"Of course," Merlini admitted. "I'm an old circus man. When I was with the Kelley & Edwards Combined Shows in '18 we had a bad 'Hey

Rube' in Hillsdale and—"

"That," Malloy said in a tired voice, "makes you our No. 1 suspect.

None of the others ever heard of the burg before."

"What," Merlini asked, "does Hillsdale, Oklahoma have to do with an invisible gunman taking potshots at an unidentified man in New York City's

Washington Square park?"

"If," Gavigan said, "I knew the answer to that I'd know what the missing motive was and which of the suspects next door is guilty."

"Next door?"

"Yes. You see, James J. Vanpool, the man who was in the park and saw the victim fall, phoned the police—"

"The paper," Merlini put in, "says he lives across the park on Washington Square South. I think I've seen him going in next door. Is he a short, fat, middle-aged man—the jolly, effervescent type—horn-rimmed glasses, military mustache?"

"That's him. Son of old man Vanpool, the Wall Street Wizard, who left James and his sister, Mrs. Elsa Blackwell, a couple of million dollars apiece. She lives next door—an invalid widow who's been bed-ridden for years. Vanpool comes over nearly every evening and plays cribbage with her. And this morning he showed up in my office with a single-shot target pistol equipped with a silencer. Said he suspected it might be the death weapon. Ballistics checked it. It was."

"He says," Malloy added, "that he figured the absence of a report at the time of the shooting indicated a silencer. He had seen one on a gun in his sister's house; he looked, found the gun had been fired recently, and trotted in to us with it. Apparently no one saw the killer because he fired from a window in the Blackwell house."

"And the gun," Merlini said, "belongs to Elsa's daughter and Vanpool's niece—Diana Blackwell."

"Yeah," Malloy nodded. "But how did you—"

"I read the papers," Merlini explained. "Diana's a leading light in café society and holder of the women's skeet shooting championship."

The Lieutenant nodded. "A glamour girl and an Annie Oakley combined. And she's engaged to Count Alexis Corvoisier, a fashion designer with an accent and waves in his hair. Uncle James wants us to throw him in the can because he was in the house when the shooting occurred and could have used the gun. But that goes for Diana and her mother too."

"Why," Merlini asked, "does he put the finger on the Count?"

"Claims he's a fortune hunter," Gavigan said. "Says he checked up and discovered the Count has a wife and three children in Biarritz. He ordered Corvoisier to clear out a couple of days ago, threatening, if he didn't, to tell Diana."

"Which means," Merlini said, "that the Count has reason to take a potshot at Uncle James. And Uncle, to save the family honor, might be tempted to do the same to the Count."

"And that's not the half of it," Gavigan added. "Mrs. Blackwell's will leaves everything to Diana, and the old lady claims her daughter and the Count have been trying to poison her. Diana says her mother has delusions, that ten years of confinement in a bed has given her a Grade-A persecution complex. Could be. The old lady won't let anyone come up to the third floor where she lives, except brother James."

"That dough," Malloy said, "is a terrific motive just the same—two million bucks worth. And if the old lady thinks Diana and her boy friend are trying to get her, she has a motive too; she might try to save herself by getting them first. Also, if Diana has heard, as Uncle James has, that her fiancé is already married, I can see her giving the Count the business."

"A situation," Merlini said, "almost as explosive as nuclear fission. Vanpool, Diana, and her mother have motives to kill the Count; the Count has reason to knock off Vanpool, and Diana and her mother each have a reason to polish off the other. But you said something about a missing motive, Inspector? Seems to me you've got more motives now than you can use."

"I know," Gavigan growled. "Motives for a lot of people who didn't get killed—at least not yet. But wait until you hear who the victim was."

"I've been wondering when you'd get to that. You've identified him?"

Gavigan looked unhappier than ever. "I'm afraid so. We showed the old lady a photo and had the others view the body. They all swear they never set eyes on the guy before. So we gave them all lie-detector tests and got exactly the same answer, plus the fact that none of them has ever been in or anywhere near Hillsdale, Oklahoma."

"And that," Merlini asked, "is where the victim hails from?"

"Yes. When we found the guy's mustache was a phony and his hair was dyed grey, we figured his glasses might be part of a disguise too. Then Malloy remembered a teletype message describing a wanted embezzler: Name: Wilbur Sloan; Age: 49; Height: 5 foot 2 inches; Weight: 193; sandy hair, mole on left hip, and so on. It all checked. Wilbur took it on the lam out of Hillsdale with thirty grand a week ago just one jump ahead of the bank examiners. They found his accounts shy another fifty thousand over the last six months and evidence that some of his best friends were bookmakers. We've established that he arrived in New York the morning of the day he was murdered and it's the first time in his life he's ever been out of Oklahoma."

"I see now," Merlini said, "what you mean by a missing motive. Nearly everybody next door has motives for killing off each other but nobody has one for killing Wilbur. And yet one of them shot him dead. But what bothers you, Inspector? That obviously means that he lost his life for the same reason he lost all that money on the horses. And, of course, that tells you who killed him."

"Huh?" Gavigan shook his head dizzily. "I don't get it..."

"Wilbur Sloan," Merlini explained, "lost money on the horses for the same reason anybody does—because he was unlucky. Since none of the persons with opportunity and means had any reason to kill Wilbur and yet one of them did just that, it obviously means that Wilbur, as unlucky as ever, was killed by accident—because in the dusk and from across the street the killer mistook him for someone else!"

"Five foot two," Gavigan said. "Weight, 193. That makes him short and fat. He was wearing a mustache, glasses, and grey hair. The only other person who fits that description is—" "Vanpool," Malloy finished.

"Yes." Merlini nodded. "But it's even simpler than that. Uncle James was the only one of the lot who, like Wilbur, was out there in the park—on his way across for his evening game of cards with his sister. Therefore, he was the only one of the lot for whom the bank embezzler could have been mistaken. The killer, waiting at the window for Vanpool, shot and killed the wrong man—the one who merely looked like Vanpool."

Gavigan was already on his feet as Merlini finished. "The murderer is, therefore, the one and only person in the house who had a motive for killing Uncle James J. Vanpool—"

"Excuse us," Malloy said, grabbing his hat. "We've got to go and arrest a Count!"