I'm having trouble with the translation of 終わらせている in the following sentence, and as far as I understand it likely translates here as "die". But I never found this meaning for 終わる in vocabulary, and why is it in させる form ?
「ええ・・・・・・摩夜さんこそ、犯人が狙う本命だと思うんです」 「いったい・・・・・・誰がそんなことを・・・・・・?」 「それは・・・・・・」 ついさっきまで、詩音さんがやっていると思っていた。 でも彼女は死んでしまった。 だとしたら摩夜さんはもう安全だと思うのだけど・・・・・・ それともーー既に終わらせているのだろうか・・・・・・?
Some sort of translation: "Until a moment ago, I though it was Shion-san. But she is dead. In this case I think that Maya-san is safe now... or - already dead."
死ぬ。
listed as meaning six in 大辞林, so that meaning is listed in dictionaries.