Learn German: Der Journalist recherchiert, warum der Unfall passiert ist. - The journalist is researching why the accident happened.

The second part of the sentence is an indirect question starting with the question word warum (why). In German, indirect questions act as subordinate clauses. This means the conjugated verb (here, ist) gets pushed to the very end of the clause. If it were a normal, direct question, the verb would come second: Warum ist der Unfall passiert?

In the second clause, why does the past participle passiert come before ist?

In a standard sentence using the perfect tense, the helping verb comes second and the past participle goes to the end. But because this is an indirect question, the conjugated helping verb (ist) is forced to the absolute end of the sentence. This naturally places it right after the past participle (passiert).

Why do we use ist instead of hat with passiert?

The verb passieren (to happen) uses sein (to be) as its helping verb for the past tense, not haben. Verbs that describe an event occurring, a change of state, or movement usually take sein.

Is recherchiert related to the English word "research"?

Yes! The verb recherchieren means to research or investigate, and it is commonly used for journalistic, academic, or police work. As a bonus tip: because it is a verb ending in -ieren, it doesn't take a ge- prefix in the past tense (for example: er hat recherchiert).