Setting aside the whole grim story of Sir Charles’s death, we had a line of inexplicable incidents all within the limits of two days, which included the receipt of the printed letter, the black-bearded spy in the hansom, the loss of the new brown boot, the loss of the old black boot, and now the return of the new brown boot.
There are no more uses of "inexplicable" in the book.
Show samples from other sources
With that he turned away and once again started inexplicably walking toward the wall.
James Dashner -- The Scorch Trials
For some inexplicable reason, those words popped into Thomas’s mind.