The last city on Detective Max Hornung's agenda was Berlin.

His friends the computers were waiting for him. Max spoke to the exclusive Nixdorf computer, to which one had access only with a specially punched card. He talked to the great computers at Allianz and Schuffa and to the ones at the Bundeskrimalamt at Wiesbaden, the collection point for all criminal activity in Germany.

What can we do for you? they asked.

Tell me about Walther Gassner.

And they told him. When they were through telling Max Hornung their secrets, Walther Gassner's life was spread out before Max in beautiful mathematical symbols. Max could see the man as clearly as if he were looking at a photograph of him. He knew his taste in clothes, wines, food, hotels. A handsome young ski instructor who had lived off women and had married an heiress much older than himself.

There was one item that Max found curious: a cancled check made out to a Dr. Heissen, for two hundred marks. On the check was written "For consultation." What kind of consultation? The check had been cashed at the Dresdner Bank in Dusseldorf. Fifteen minutes later Max was speaking to the branch manager of the bank. Yes, of course the branch manager knew Dr. Heissen. He was a valued client of the bank.

What kind of doctor was he?

A psychiatrist.

When Max had hung up, he sat back, his eyes closed, thinking. A loose thread. He picked up the telephone and placed a call to Dr. Heissen in Dusseldorf.

An officious receptionist told Max that the doctor could not be disturbed. When Max insisted, Dr. Heissen got on the telephone and rudely informed Max that he never revealed any information about his patients, and that he would certainly not dream of discussing such matters over the telephone. He hung up on the detective.

Max went back to the computers. Tell me about Dr. Heissen, he said.

Three hours later Max was speaking to Dr. Heissen on the telephone again.

"I told you before," the doctor snapped, "that if you want any information about any of my patients, you will have to come to my office with a court order."

"It is inconvenient for me to come to Dusseldorf just now," the detective explained.

"That's your problem. Anything else? I'm a busy man."

"I know you are. I have in front of me your income tax reports for the past five years."

"So?"

Max said, "Doctor, I don't want to make trouble for you. But you are illegally concealing twenty-five percent of your income. If you prefer, I can just forward your files to the German income tax authorities and tell them where to look. They could start with your safe-deposit box in Munich, or your numbered bank account in Basel."

There was a long silence, and then the doctor's voice asked, "Who did you say you were?"

"Detective Max Hornung of the Swiss Kriminal Polizei."

There was another pause. The doctor said politely, "And what is it exactly you wish to know?"

Max told him.

Once Dr. Heissen began talking, there was no stopping him. Yes, of course he remembered Walther Gassner. The man had barged in without an appointment and had insisted on seeing him. He had refused to give his name. He had used the pretext that he wanted to discuss the problems of a friend.

"Of course, that alerted me instantly," Dr. Heissen confided to Mox. "It is a classic syndrome of people unwilling or afraid to face their problems."

"What was the problem?" Max asked.

"He said his friend was schizophrenic and homicidal, and would probably kill someone unless he could be stopped. He asked if there was some kind of treatment that could help. He said he could not bear to have his friend locked away in an insane asylum."

"What did you tell him?"

"I told him that first, of course, I would have to examine his friend, that some types of mental illness could be helped with modern drugs and other psychiatric and therapeutic treatments, and that other types were incurable. I also mentioned that in a case such as he described, treatment might be necessary for an extended period of time."

"What happened then?" Max asked.

"Nothing. That was really all. I never saw the man again. I would like to have helped him. He was very distraught. His coming to me was obviously a cry for help. It is similar to a killer who writes on the wall of his victim's apartment, 'Stop me before I kill again!'"

There was one thing still puzzling Max. "Doctor, you said he wouldn't give you his name, and yet he gave you a check and signed it."

Dr. Heissen explained, "He had forgotten to bring any money with him. He was very upset about that. In the end he had to write the check. That's how I happened to learn his name. Is there anything else you need to know, sir?"

"No."

Something was disturbing Max, a loose thread dangling tantalizingly out of reach. It would come to him - meanwhile, he had finished with the computers. The rest was up to him now.

When Max returned to Zurich the following morning, he found a teletype on his desk from Interpol. It contained a list of customers who had purchased the batch of raw stock used to make the snuff murder film.

There were eight names on the list.

Among them was Roffe and Sons.

Chief Inspector Schmied was listening to Detective Max Hornung make his report. There was no doubt about it. The lucky little detective had stumbled onto another big case.

"It's one of five people," Max was saying. "They all have a motive and they had the opportunity. They were all in Zurich for a board meeting the day the elevator crashed. Any one of them could have been in Sardinia at the time of the Jeep accident."

Chief Inspector Schmied frowned. "You said there were five suspects. Aside from Elizabeth Roffe, there are only four members of the board. Who's your other suspect?"

Max blinked and said patiently, "The man who was in Chamonix with Sam Roffe, when he was murdered. Rhys Williams."