。
She has absolutely nothing to do with the case.
Literal
She [topic-は] that case [target-には] completely connection-not.
The には here stacks に (target) with は (contrastive), adding emphasis: 'as for that case specifically, no involvement.' まったく ('completely, utterly') paired with 関係ない gives absolute denial. This kind of emphatic structure is the canonical phrasing suspects, witnesses, or defenders use to disclaim involvement — the stacking of まったく with contrastive は makes the denial unambiguous. 関係ない is a colloquial contraction of 関係がない, with the が dropped in casual speech.