The Passengers

Of the 227 passengers, 152 were Chinese citizens, including a group of 19 artists with six family members and four staff returning from a calligraphy exhibition of their work in Kuala Lumpur; 38 passengers were Malaysian. The remaining passengers were from 13 different countries.[28][36] Twenty passengers—12 of whom were from Malaysia and eight from China—were employees of Freescale Semiconductor.[37][38]

There is nothing about the passengers that give cause for concern other than two were traveling on forged passports.

The authorities discounted them being an issue very early on…. which has always puzzled me.