I know that 訊く is another way to write 聞く, so now I'm curious as to why the author of the book used it here instead of 聞く, which has been used for all previous instances in the book.
こちらから訊くより先に、低く呟くような声が返ってきた。
As I've mentioned in What is the definition of 凶々? , I'm wondering if there are any nuances or slightly different meanings when it comes to using different kanji that have the same-ish dictionary definition and how to understand the why or to discern the meaning behind the seemingly random different kanji being used in sentences.
For example, what is the difference between
こちらから訊くより先に、低く呟くような声が返ってきた。
and
こちらから聞くより先に、低く呟くような声が返ってきた。