翻译 我不知道他们是这种人。

i don't know that he is a man of this kind

“赤脚的光头 ”也不全对呀！注意是“他们”，而不是“他”，所以，正确的表达法是：
I didn't know they were such kind of people .
或：
I don't know they are such kind of people.

I didn't know they were such kind of people.

I did not know they are such person

I don't know he is this description.

I don't know they are of such kind.