As he left the office my Chinese clerk came in with a number of passes for me to initial. In order to protect employers of Chinese labour, no coolie was allowed to leave any of the native States without a pass. Before a man could obtain a pass he had to produce from his employer a certificate giving his name and province and stating that he owed nothing to the mine or estate. This was attached to the pass, which was in English and Malay, and signed by the chief police-officer. On every road, at its junction with the neighbouring State, was a police-station, where all passes were examined. "So-and-so, Fuhkien," began the clerk, putting the letters down in front of me, one by one, to be initialed. What was it Cassim had said? "Ah Sing says the men spoke the Fuhkien dialect." Now, the robbers would not attempt to dispose of the stolen property in the State where the robbery had been committed. They knew that every police-station and pawnshop had been warned. They would therefore try and take it out of the country. I would mark every Fuhkien's pass and have him searched at the frontier station he tried to leave by. "Hold on," I said; "I have not been listening to what you read out. Begin again." He did so, and I initialed every Fuhkien's pass in red pencil, those of other provinces in blue. When the passes were brought in, I also signed all the Fuhkiens' in red ink. I then telegraphed to each frontier station:-- "Search all Chinese whose passes are signed in red ink; detain all who cannot account satisfactorily for their property, and report." At six that evening I received a telegram in Malay from one of the police-stations:-- "Eleven Chinese with passes signed in red ink arrested this afternoon, accompanied by a bullock cart in which is a box containing clothing and jewellery and seven hundred dollars. Can give no satisfactory account of themselves." Within half an hour a sergeant and six Sikhs were on their way to bring the Chinamen to head-quarters. They arrived the following morning, and I at once sent for Ah Sing. As soon as he entered the charge-room he exclaimed:-- "Why, Tuan, there is my box which the robbers took away; it has my 'chop' on it!" Sure enough it was, and it contained all the stolen property, tallying exactly with his description, even to the rolls of dollars in the "chopped" wrappers. If ever a detective was astonished, Sergeant Cassim was. "Who has won the hundred dollars, Tuan?" he asked. "I have," I replied. "But how did the Tuan discover it?" "You gave me the clue yourself," I said. "You told me the robbers spoke the Fuhkien dialect, so I signed all the Fuhkien passes in red ink, and ordered that every man with one of these was to be searched at the frontier stations." "The Tuan was right," cried Cassim. "Every man leaves some trace of his crime, and I thank the Tuan for proving it to me."