On December 26, after clashes between police and protesters, in the afternoon when an ASTV reporter is interviewing a protester who has been injured (after she asks him about his injuries and what happened, and what did the police do to him), she asks him “where there any Cambodians? Cambodian police?” (“แล้วๆ มีเขมรด้วยไม๊คะ ตำรวจเขมร มีไม๊”). From around 1:20 minute mark:

BP: The reporter doesn’t really get a positive answer to her questions, but there is a reason she is asking these questions….

On December 26, on the Ratchadomnern protest stage in the evening is one of the regular speakers, (บุญส่ง ชเลธร/Boonsong Chaletorn).* He is relaying to the crowd the events of that day as he experienced them. He says there are some truths that he wants to tell the crowd which is that half of the police in black were Cambodians; they are Cambodian soldiers. He says they paid them Cambodian money to Cambodian fighters. They brought Cambodians to shoot us. Cambodian soldiers to kill the people. From around the 19:30 minute mark for around 40 seconds and again (the kill us reference) at 21:55:

BP: The clear implication from this inflammatory rhetoric is that it makes it easier for the protesters** to feel justified in physically attacking the police because the police are not Thais; they are just Cambodian mercenaries (no doubt paid personally by the evil one, and of course, paid in Cambodian money because that is the only type of money that Cambodian mercenaries would accept). Expect to see a continuation of this rhetoric as the protesters up the ante…

*He is/was a Professor of Economics at Rahmkamhaeng; he was a former student activist during the 70s and lived for decades in Sweden.