> 「犯人**とはいわないまでも**何があったのか尋問できるのはお姉ちゃんだけだ！」

Does this pattern have the same meaning as the one explained here: https://japanese.stackexchange.com/questions/30100/とまではいかないまでも-meaning?

I think it is different from the explanation linkend above. The linked example ‘includes’ statement A and B as true, while here statement A (犯人) is ’excluded’ while statement B (尋問できる) is ‘included’ as property of 「お姉ちゃん」
(Translated along the lines of "not going as far as to say that something/someone/etc. is X but something/someone/etc. (obviously) is Y ")