Speculation may usefully provide leads to investigate, but it's meaningless as a conclusion and won't be accepted by scientists or anyone else serious (including courts); they require evidence.

> you can’t always make a definitive statement

It's far short of that. Human speculation is wildly unreliable and we seem to always overestimate it, perhaps because it's emotionally satisfying: What other speculative answer would we choose but something that satisfies our emotions? Lacking evidence, nothing compels us to face the unpleasant or unexpected. Look what our understanding of nature and the world was before we required evidence (before science).