"True!" Maruffi agreed. "Being a Palermitan myself, he is real to me, but, as you say, n.o.body knows."

He rose and shook hands cordially with both men. When he had joined the group of Italians at a near-by table, Donnelly said:

"There's the whitest dago in the city. I thought he might be the 'One Who Knows,' but I reckon I was mistaken. He could help me, though, if he dared."

"Have you confided in him?"

"Lord, no! I don't trust any of them. Say! The more I think about that letter, the more I think it's a bluff."

"You can't afford to ignore it."

"Of course not. I'll plant O'Connell and another man outside on Thursday night and see if anything suspicious turns up, but I'll take my dinner elsewhere."

The two men had finished their meal when Bernie Dreux strolled in and took the seat which Maruffi had vacated.

"Well, how goes your detecting, Bernie?" Norvin inquired.

"_Hist_!" breathed the little man so sharply that his hearers started. He winked mysteriously and they saw that he was bursting with important tidings. "There's something doing!"

"What is it?" demanded the Chief. But Mr. Dreux answered nothing.

Instead he lit a cigarette, and as he raised the match looked guardedly into a mirror behind Donnelly's chair.

"I'm glad you took this table," he began in a low voice. "I always sit where I can get a flash."

"A _what_?" queried the astonished Blake.

"Pianissimo with that talk!" cautioned the speaker. "You'll tip him off."

"Tip who?" Donnelly breathed.

"My man! He's one of the gang. Do you see that fellow--that wop next to Caesar Maruffi?" Bernie did not lower his eyes from the mirror, "the third from the left."

"Sure!"

"Well!" triumphantly.

"Well?"

"That is he."

"That's who?"

"I don't know."

"What the--"

"He's one of 'em, that's all I know. I've been on him for a week. I've trailed him everywhere. He has an accomplice--a woman!"

The Chief's face underwent a remarkable change. "Are you sure?" he whispered, eagerly.

"It's a cinch! He comes to the fruit-stand every day. I think he's after blackmail, but I'm not sure."

"Good!" Dan exclaimed. "I want you to trail him wherever he goes, and, above all, watch the woman. Now tear back to your banana rookery or you'll miss something. Better have a drink first, though."

"I'll go you; it's tough work on the nerves. I'm all upset."

"I thought you never drank whiskey," Norvin said, still amazed at the extraordinary transformation in his friend.

"I don't as a rule, it kippers my stomach; but it gives me the courage of a lion."

Donnelly nodded with satisfaction. "Don't get pickled, but keep your nerve. Remember, I'm depending on you."

Dreux's slender form writhed and shuddered as he swallowed the liquor, but his eyes were shining when he rose to go. "I'm glad I'm making good," said he. "If anything happens to me, keep your eye skinned for that fellow; there's dirty work afoot."

When he had gone Donnelly stuck his napkin into his mouth to still his laughter. "'There's dirty work afoot,'" he quoted in a strangling voice. "Can you beat that?"

"I--can't believe my senses. Why, Bernie's actually getting tough! Who is this fellow he's trailing?"

"That? That's Joe Poggi, the owner of the fruit-stand. He's my best dago detective, and I sent him here to-night in case anything blew off. The woman is his wife--lovely lady, too. 'Blackmail!' Oh, Lord!

I'll have to tell Poggi about this. I'll have to tell him he's being shadowed, too, or he'll stop suddenly on the street some day and Bernie will run into him from behind and break his nose."

Thursday night pa.s.sed without incident. Donnelly set a watch upon the Red Wing Club, but nothing occurred to give the least color to the written warning. In the course of a fortnight he had well-nigh forgotten it, and when a third letter came he was less than ever inclined to believe it genuine.

"You forestalled the first attempt upon your life," wrote the informant, "but another will be made. You are to be shot at Police Headquarters some night next week. Your desk stands just inside a window which opens upon the street. A fight will occur at the corner near by and during the disturbance an a.s.sa.s.sin will fire upon you out of the darkness, then disappear in the confusion. Do not treat this warning lightly or I swear that you will repent it.

"ONE WHO KNOWS"

Donnelly showed this to Blake, saying, sourly, "You see. It's just as I told you. They're trying to run me out."

"What are you going to do?"

"I'm going to move my desk, for one thing, then I'm going to run down this writer. O'Connell is going through the stationery-stores now, trying to match the water-mark on the paper. The post-office is on the lookout for the next letter and will try to find which mail-box it is dropped into."

"Then you think there will be other letters to follow this one?"

"Certainly! When they see that I've moved away from that window they'll think they've got me going, then I'll be warned of another plot, and another, and another. It might work with some people." The speaker's lips curled in a wintry smile.

"You no longer think it came from one of the Pallozzo gang?"

"No! There's n.o.body in the outfit who can write a letter like that.

It's from the Mafia."

"How can you say that when the same writer betrayed Narcone?"

"Oh, I've asked myself the same question," Donnelly answered with a trace of exasperation, "and I can't answer it unless that was merely a case of revenge. Take it from me, I'll get another letter inside of ten days. See if I don't."

True to his prediction, the tenth day brought another warning. The writer advised him that his enemies had changed their plans once more, but would strike, when the first opportunity offered. As to where or when this would occur, no information was given. The Chief was merely urged in the strongest terms to remove himself beyond the possibility of danger.