Undesirable people

At the moment there is an exchange from Kakogawa City to Waitakere City in New Zealand. There are around 12 students and two teachers that have come from Kakogawa.

Today they went to Auckland Museum and unfortunately the minibus was broken into and their belongings such as passports and other stuff that would have been in their bags has all been taken. This was their first day in New Zealand and most of the students are still at Chuugakkou. When the Japanese think of New Zealand they certainly do not associate it with crime like this.

What word/s would the Japanese use to refer to people like thieves or criminals that is to an extent derogatory? For example in English we might say "Bastards! or ~Scumbag!" What would be the most common word/s?

i think the word you are looking for is "gaijin"

Oh for goodness sake, "gaijin" is not the word THEY're looking for. I think terms like "kuzu" would be appropriate, although uneducational.

Btw, I really feel sorry for these kids, but I think it was their responsibility or at least the teachers' and tour guides' responsibility to have let them left their valuables behind. It's common sense not to let go of them.

Some one should have discussed this with them:
NEVER, NEVER, NEVER, leave your passport unsecure in ANY country!
They should have taken them with them when they left the bus.

I agree with Uco that while there are a few words (such as the one she quoted) that may suit the occasion, it would be uneducational, and also coming from a non-Japanese, it would sound... quite strange. The habit of using strong words is different between English and Japanese languages, I'd say.

Yes, and while I do feel sorry for the schoolkids, there should have been better instructions about taking care of their valuables. I hope the guide/teacher can help them immediately with the re-issuance of passports at the embassy and things, and that the kids would be able to enjoy at least a little of the trip without this initial incident dragging them down excessively!