därför att

Conjunction

 * 1) for the reason that ...; because, since, as

Usage notes
Compare:
 * Eftersom de tror vi är onda andar (så) skjuter de på oss
 * De skjuter på oss därför att de tror vi är onda andar

Similar to how "For the reason that they think we're evil spirits, they're shooting at us" is unusual phrasing in English, "eftersom" sounds more natural in the first sentence. In the second sentence, both "därför att" and "eftersom" sound natural. "Därför att" can more or less always be replaced with "eftersom" or "."

Compared to "eftersom" and "för att," "därför att" has a flavor of being somewhat more formal, strict, and indicating that the line of argument needed is not necessarily trivial (somewhat similar to "for the reason that ...")