"What every sane man thinks," answered Miller. "That the prosecution will have to secure more material and tangible proof before it can secure an indictment by the Grand Jury."

"I'm not so certain of that," responded the detective, ruffled by Miller's casual manner. "Our evidence against Miss Whitney was pretty conclusive."

"It would have been just as conclusive if applied to any other inhabitant of the Whitney house that night."

"Hardly." Mitchell smiled broadly. "I fear your friendship blinds you to the danger in which Miss Whitney stands."

Miller refrained from answering until their waiter had served the coffee and cheese and departed. "Circumstantial evidence will not always convict--fortunately," he said, helping himself to the Camembert. "What have you proved...."

"That Spencer was Miss Whitney's rejected lover," broke in Mitchell.

"That the knife belonged to her; that she tried to remove incriminating blood stains on his shirt with her perfumed handkerchief; and that he held in his hand a flower, possibly broken from the bouquet which she was wearing at the time."

"It sounds formidable," commented Miller quietly. "But there are a number of flaws. You have _not_ absolutely proved that the knife belonged to Miss Whitney, only proved that it is probable she might have owned it.

Wait"--as Miller started to interrupt. "The deputy coroner testified that Spencer was killed by cyanide of potassium."

"Which, as Spencer did not swallow it, was administered by aid of the knife," retorted Mitchell hastily.

"The deputy coroner said he found no trace of the poison on the knife blade." Miller paused to refill Mitchell's coffee cup. "Secondly, cyanide of potassium is not a drug which Miss Whitney would be apt to have around."

"I saw a half-filled bottle of it in Whitney's work-shop last Wednesday."

"Quite true, I saw it there myself," admitted Miller. "I also saw that Whitney kept his studio workshop under lock and key."

"To outsiders; but it is just possible he is not so strict about the members of his household, his testimony to the contrary," argued Mitchell. "The point is not well taken, Captain, and even if it were," he stirred his coffee thoughtfully, "Miss Whitney did not need to enter her father's workshop to secure the cyanide of potassium; I find she buys all his photographic supplies at a shop not far from here, and recently purchased a new supply of cyanide."

"Purely circumstantial evidence," responded Miller, keeping his expression unaltered by an effort. The detective's last statement had startled him. "In regard to the flower which Spencer held in his hand: you say it was probably broken from the bouquet which she wore at the time of committing the crime--I am, for the sake of argument only, admitting that she might be guilty. The medical evidence went to prove that Spencer was killed between three and four in the morning; it is straining probabilities to claim that a young girl, in donning her wrapper, pinned on a bouquet of flowers."

"How do you know she was not fully dressed? It was not so late in the morning; she could have gone to bed after the crime, or she may not have gone to bed at all."

"All supposition," scoffed Miller.

"Not quite all." The detective, nettled by his jeering smile, spoke hastily. "On further inquiry I learned from one of the servants today that Miss Whitney had on the same dress Wednesday morning, when her screams aroused the household, which she wore at dinner the night before."

"Ah, indeed?" Miller's smile had ceased to be skeptical, it was strained.

"And which servant imparted that information to you?"

"Henry, the chauffeur."

"For a chauffeur, Henry seems to know a great deal about what transpires inside the Whitney house," observed Miller thoughtfully. "Tell me, Mitchell, what motive do you attribute to Miss Whitney for the killing of Sinclair Spencer?"

Mitchell looked uncomfortable, and it was not until Miller repeated his question that he spoke. "I believe Spencer persuaded Miss Whitney to meet him clandestinely that night, and threatened to compromise her if she refused again to marry him."

"Oh, come!" Miller spoke more roughly than he realized. "Wake up, Mitchell; you've been reading penny dreadfuls. Try and think up a motive which will hold water."

The detective flushed. "That is quite motive enough," he said. "If Miss Whitney takes the stand in her own defense she can, on that motive, enter a plea of killing to protect her honor...."

"And any jury in the country would acquit her," broke in Miller. "She would...."

"Thus escape the gallows," finished the detective.

"But I can suggest an even better solution of the problem," put in Miller suavely, although his fingers itched to choke his companion.

"And that is--?"

"That the detective force find the guilty party."

Mitchell suppressed a smile. "And where would you suggest that we hunt for this guilty party?" he asked. "Provided he or she is still at large, and not out on bail under indictment."

"Search among the men and women who spent Wednesday night at the Whitneys', servants as well as guests."

"Captain," in his earnestness Mitchell leaned across the table, "it is contrary to all records of crime that a man or woman will commit murder without motive...."

"You forget homicidal maniacs."

"True, but they do not belong in this category," protested Mitchell.

"No person in that house, except Miss Whitney, had a motive for killing Spencer."

"Motives are not always on the surface; I advise you to investigate ..."

"Yes--?" eagerly.

"Is it true that arc lights have been installed at the United States navy yards and arsenals, which make them as light as day on the darkest night?"

"I believe so." Mitchell glanced perplexedly at his companion. Why was he changing the conversation?

"And that visitors are not encouraged to loiter on government reservations?"

"I believe such an order has been issued," conceded the detective.

"Also visitors are forbidden at the Government Radio Station at Arlington?"

"Yes."

"And still there is a leak--government secrets are secrets no longer."

"How do you know that, Captain?" and the detective shot a look full of suspicion at him.

"I only know what Senator Foster has told me," carelessly. "I believe Foster's advice has been sought in the matter."

"And why did he confide in you?"

"He desired my help," responded Miller. "Seemed to think my opinion might be worth something, but, honestly, Mitchell, I can't see anything to this secret leak business--the Secret Service operatives are putting a scare over on the government.

"It's more than that, sir. No more coffee," and the detective, his sudden doubts dispelled by Miller's sunny smile, leaned back once more in his chair. "It seems that officials here are awakening to the realization that government secrets are being betrayed. If the American troops are ordered to a certain point on the border, the order is known in Mexico before it is executed. It is the same with coded communications to Foreign Powers. The movements of our fleet are known to foreign naval attaches even before the maneuvers are carried out. The whereabouts of the smallest torpedo boat and submarine is no secret--to any but the American people."

"Is that so?" Miller looked politely incredulous. "And is the Secret Service not investigating the matter?"

"Sure; they'll handle it all right." Mitchell twisted about in his chair.