The seven-story headquarters building of Interpol, the International Criminal Police Organization, is at 26 Rue Armengaud, in the hills of St. Cloud, about six miles west of Paris, discreetly hidden behind a high green fence and white stone walls. The gate at the street entrance is locked twenty-four hours a day, and visitors are admitted only after being scrutinized through a closed-circuit television system. Inside the building, at the head of the stairs at each floor, are white iron gates which are locked at night, and every floor is equipped with a separate alarm system and closed-circuit television.

The extraordinary security is mandatory, for within this building are kept the world's most elaborate dossiers with files on two and a half million criminals. Interpol is a clearinghouse of information for 126 police forces in 78 countries, and coordinates the worldwide activities of police forces in dealing with swindlers, counterfeiters, narcotics smugglers, robbers, and murderers. It disseminates up-to-the-second information by an updated bulletin called a circulation; by radio, photo-telegraphy, and early-bird satellite. The Paris headquarters is manned by former detectives from the S��ret�� Nationale or the Paris Pr��fecture.

On an early May morning a conference was under way in the office of Inspector Andr�� Trignant, in charge of Interpol headquarters. The office was comfortable and simply furnished, and the view was breathtaking. In the far distance to the east, the Eiffel Tower loomed, and in another direction the white dome of the Sacr�� Coeur in Montmartre was clearly visible. The inspector was in his mid-forties, an attractive, authoritative figure, with an intelligent face, dark hair, and shrewd brown eyes behind black horn-rimmed glasses. Seated in the office with him were detectives from England, Belgium, France, and Italy.

"Gentlemen," Inspector Trignant said, "I have received urgent requests from each of your countries for information about the rash of crimes that has recently sprung up all over Europe. Half a dozen countries have been hit by an epidemic of ingenious swindles and burglaries, in which there are several similarities. The victims are of unsavory reputation, there is never violence involved, and the perpetrator is always a female. We have reached the conclusion that we are facing an international gang of women. We have identi-kit pictures based on the descriptions by victims and random witnesses. As you will see, none of the women in the pictures is alike. Some are blond, some brunet. They have variously been reported as being English, French, Spanish, Italian, American  -  or Texan."

Inspector Trignant pressed a switch, and a series of pictures began to appear on the wall screen. "Here you see an identi-kit sketch of a brunet with short hair." He pressed the button again. "Here is a young blonde with a shag cut.... Here is another blonde with a perm... a brunet with a pageboy.... Here is an older woman with a French twist... a young woman with blond streaks... an older woman with a coup sauvage". He turned off the projector. "We have no idea who the gang's leader is or where their headquarters is located. They never leave any clues behind, and they vanish like smoke rings. Sooner or later we will catch one of them, and when we do, we shall get them all. In the meantime, gentlemen, until one of you can furnish us with some specific information, I am afraid we are at a dead end...."

When Daniel Cooper's plane landed in Paris, he was met at Roissy-Charles de Gaulle Airport by one of Inspector Trignant's assistants, and driven to the Prince de Galles, next door to its more illustrious sister hotel, the George V.

"It is arranged for you to meet Inspector Trignant tomorrow," his escort told Cooper. "I will pick you up at eight-fifteen."

Daniel Cooper had not been looking forward to the trip to Europe. He intended to finish his assignment as quickly as possible and return home. He knew about the fleshpots of Paris, and he had no intention of becoming involved.

He checked into his room and went directly into the bathroom. To his surprise, the bathtub was satisfactory. In fact, he admitted to himself, it was much larger than the one at home. He ran the bath water and went into the bedroom to unpack. Near the bottom of his suitcase was the small locked box, safe between his extra suit and his underwear. He picked up the box and held it in his hands, staring at it, and it seemed to pulse with a life of its own. He carried it into the bathroom and placed it on the sink. With the tiny key dangling from his key ring, he unlocked the box and opened it, and the words screamed up at him from the yellowed newspaper clipping.

BOY TESTIFIES IN MURDER TRIAL

Twelve-year-old Daniel Cooper today testified in the trial of Fred Zimmer, accused of the rape-murder of the young boy's mother. According to his testimony, the boy returned home from school and saw Zimmer, a next-door neighbor, leaving the Cooper home with blood on his hands and face. When the boy entered his home, he discovered the body of his mother in the bathtub. She had been savagely stabbed to death. Zimmer confessed to being Mrs. Cooper's lover, but denied that he had killed her.

The young boy has been placed in the care of an aunt.

Daniel Cooper's trembling hands dropped the clipping back into the box and locked it. He looked around wildly. The walls and ceiling of the hotel bathroom were spattered with blood. He saw his mother's naked body floating in the red water. He felt a wave of vertigo and clutched the sink. The screams inside him became gutteral moans, and he frantically tore off his clothes and sank down into the blood-warm bath.

"I must inform you, Mr. Cooper," Inspector Trignant said, "that your position here is most unusual. You are not a member of any police force, and your presence here is unofficial. However, we have been requested by the police departments of several European countries to extend our cooperation."

Daniel Cooper said nothing.

"As I understand it, you are an investigator for the International Insurance Protective Association, a consortium of insurance companies."

"Some of our European clients have had heave losses lately. I was told there are no clues."

Inspector Trignant sighed. "I'm afraid that is the case. We. know we are dealing with a gang of very clever women, but beyond that  - "

"No information from informers?"

"No. Nothing."

"Doesn't that strike you as odd?"

"What do you mean, monsieur?"

It seemed so obvious to Cooper that he did not bother to keep the impatience out of his voice. "When a gang is involved, there's always someone who talks too much, drinks too much, spends too much. It's impossible for a large group of people to keep a secret. Would you mind giving me your files on this gang?"

The inspector started to refuse. He thought Daniel Cooper was one of the most physically unattractive men he had ever met. And certainly the most arrogant. He was going to be a chierie, "a pain in the ass"; but the inspector had been asked to cooperate fully.

Reluctantly, he said, "I will have copies made for you." He spoke into an intercom and gave the order. To make conversation, Inspector Trignant said, "An interesting report just crossed my desk. Some valuable jewels were stolen aboard the Orient Express while it  - "

"I read about it. The thief made a fool of the Italian police."

"No one has been able to figure out how the robbery was accomplished."

"It's obvious," Daniel Cooper said rudely. "A matter of simple logic."

Inspector Trignant looked over his glasses in surprise. Mon Dieu, he has the manners of a pig. He continued, coolly, "In this case, logic does not help. Every inch of that train was examined, and the employees, passengers, and all the luggage searched."

"No," Daniel Cooper contradicted.

This man is crazy, Inspector Trignant decided. "No  -  what?"

"They didn't search all the luggage."

"And I tell you they did," Inspector Trignant insisted. "I have seen the police report."

"The woman from whom the jewels were stolen  -  Silvana Luadi?"

"Yes?"

"She had placed her jewels in an overnight case from which they were taken?"

"That is correct."

"Did the police search Miss Luadi's luggage?"

"Only her overnight case. She was the victim. Why should they search her luggage?"

"Because that's logically the only place the thief could have hidden the jewels  -  in the bottom of one of her other suitcases. He probably had a duplicate case, and when all the luggage was piled on the platform at the Venice station, all he had to do was exchange suitcases and disappear." Daniel Cooper rose. "If those reports are ready, I'll be running along."

Thirty minutes later, Inspector Trignant was speaking to Alberto Fornati in Venice.

"Monsieur," the inspector said, "I was calling to inquire whether there happened to be any problem with your wife's luggage when you arrived in Venice."

"S��, s��," Fornati complained. "The idiot porter got her suitcase mixed up with someone else's. When my wife opened her bag at the hotel, it contained nothing but a lot of old magazines. I reported it to the office of the Orient Express. Have they located my wife's suitcase?" he asked hopefully.

"No, monsieur," the inspector said. And he added silently to himself, Nor would I expect it, if I were you.

When he completed the telephone call, he sat back in his chair thinking, This Daniel Cooper is tr��s formidable. Very formidable, indeed.