Leavitt knew that sacks filled with milk sugar or ordinary sugar would never fool a veteran trafficker in narcotics because the sugar would weigh ten times more than heroin. The substitute had to have the same bulk density as heroin.

For hours the chemist worked on the problem, testing different materials, but each of them was either too dense or did not meet the specifications in appearance or taste. It seemed that the agents in New York had tossed the laboratory a problem that simply could not be solved in so short a time.

Leavitt was still in the laboratory late in the evening pondering the problem when he remembered that several months earlier the laboratory had made a routine test of a white, light, powdery, silica compound produced by the Johns-Manville Company as a filter agent. Somewhere in the laboratory there was a sample of this product.

Leavitt found the sample in a storage room. He also found the product had the bulk density, weight and appearance of heroin. The remaining step was to make the stuff taste like the narcotic—give it the same bitter flavor.

At last Leavitt found the solution in a mixture of quinine and strychnine added to the filter powder in just the proper proportions. The amount of strychnine he used was in safe limits, even if a man should swallow a large amount of the stuff.

The following morning, Lerner supervised the job of emptying the sacks of heroin and filling them with the harmless substitute. He took the sacks to his secretary, Miss Alfhilde Norrman. “I’ve got a job for you, Alfy,” he said. “Can you re-sew these bags so no one can tell they’ve been tampered with?”

“I think so,” Miss Norrman said. Using the same threads with which the bags had been sewn in Hong Kong, Miss Norrman stitched them shut. She was careful to insert the needle in the old thread-holes left in the material. When the job was finished, the eight sacks appeared exactly as they were when young Halvorsen accepted them from the fat Chinese.

Less than twenty-four hours after Fleishman’s call to Lerner, the sacks of phony heroin were on their way to New York by plane. The following day, Agent Polcuch and Halvorsen flew to San Francisco, where they checked into a seaman’s hotel near the waterfront. After dinner, they carried the brief case containing the heroin substitute to the Greyhound bus station and checked it in a locker.

That same evening they met with agents from the San Francisco Customs office to make plans for the delivery of the sacks to Lew Gar Kung Saw—a name that meant nothing to the San Francisco agents, who knew every suspected narcotics trafficker on the West Coast. Very likely the name was an alias.

It was agreed Polcuch should carry a concealed radio transmitting device to the building on Clay Street. Two agents would be hidden in a small delivery truck parked on the street to record the conversation with the receiver. They would come to help Polcuch and Halvorsen if trouble should develop.