Here are some excerpts from SOLVED! The “Mysterious” Disappearance of Jim Thompson,
the Legendary Thai Silk King
(ref. ISBN: 978-1-59571-505-0):

White car at Jalan Kamunting (Chapter Nineteen, page 95)

When Thompson left the Lutheran Mission bungalow, he came into contact with the driver of a white car. After a brief exchange of words, the driver drove off. The questions that came to mind were these: Who was the driver of the vehicle? Did he know Thompson? Did he ask for directions? Was he assigned to relay a message to Thompson? Did he threaten Thompson? Was the vehicle a Malaysian registered car or was it one with a foreign license plate?

Dinner at Ye Olde Smokehouse (Chapter Twenty, pages 98 - 99)

When Thompson came to the Cameron Highlands, his first day at Moonlight bungalow was uneventful. The next morning, Dr. Ling and he got lost while exploring the woods. After lunch, he withdrew for an afternoon siesta. At about 4.30pm he got up for some tea. Later, his companions and he joined Dr. Einar Ammundsen at Ye Olde Smokehouse for dinner. After supper, they decided to call it a day. While having dinner with Dr. Ammundsen, did the Dane tell him something?

Cancellation of dinner appointment (Chapter Twenty One, page 102)

Before he came to the Highlands, Thompson made arrangements with Constance Mangskau and the Lings to head for Singapore on the morning of March 27. Dr. Ling was to drive him to the city state so that he would be able to keep his dinner appointment with Francis Joseph Galbraith, the US ambassador to Singapore and Edward Pollitz, an American businessman who was exploring the possibility of setting up a textile outfit in the republic. But a day earlier, he disappeared. What caught many by surprise was this: his appointment was cancelled before he got lost. This prompted Mangskau to ask: “Why did the embassy cancel his dinner appointment before and not after he went missing?”