Questions & Answers about De truer familien.
Here, de means they.
So De truer familien = They are threatening the family / They threaten the family.
A useful extra note: because De is at the beginning of the sentence, it is capitalized. That does not automatically mean anything special here.
It can in some contexts, but probably not here.
In older or very formal Norwegian, De with a capital D could be used as a polite form of you, similar to old-fashioned formal address in some European languages. But in modern everyday Norwegian, that usage is rare.
In this sentence, the capital D is most naturally just there because it is the first word in the sentence. So learners should usually read De truer familien as They are threatening the family.