ballpoint

Yes, I was playing devils advocate as a counter to all the knee jerk posts on the first page of the thread, especially those trying to make out this would never happen elsewhere. I actually fully go along with the Swiss guy's story. However, in my own country (NZ) if you kill someone who is on your own property illegally, you will still be investigated, and likely charged, for manslaughter. "This defence recognises that people have a right to defend themselves against violence or threats of violence, so long as the force used is no more than is reasonable for that purpose. The law does not require people to wait until they have been attacked before taking action to protect themselves. But the law also acknowledges the attacker’s right to life and bodily integrity and requires the force used in self-defence to be no more than is necessary to prevent the violence or threatened violence". NEW ZEALAND LAW COMMISSION - 3. Self-defence (nzlii.org) The UK is similar, as seen in a previous post, as is Australia: "Australian Ben Batterham is in custody until late May (the story is dated March 2016) on a murder charge after an altercation with a man he discovered in his Newcastle home. Legal experts say that case will hinge on what happened during the struggle outside the suburban home, but if one thing is certain the legal definition of defending your home against a threat has jarred with what many Australians believe is their natural right to defend themselves and their property". When victims hit back at intruders - NZ Herald The UK case above, plus a few others are also covered in this story.

So, the police should take his word and let him go? Or should they do what the police of any country would do and hold him for questioning, and maybe allow him to be released on bail, until the investigation has been carried out?

Exactly. Hence the need for an investigation.

For all those saying this will put people off coming to Thailand, I say show me a country where the police would not investigate the killing of a man on another man's property, and then I'll show you a country I wouldn't want to live in.

Yes, but the Swiss guy now has an excuse for his prints to be on the gun.