Case closed
Somebody closed The Prize Marrow Affair. Your turn.
They found the contradiction without being told where it was. Open the same case and see whether your first three questions get you there.

Cozy · an English village, late summer 1954, the annual marrow-judging tent at the Little Wickham summer fete
The Prize Marrow Affair
Cyril Pettigrew lies dead in the marrow-judging tent at the Little Wickham summer fete — and of the four souls who lingered near, one is a murderer.
4 suspects · medium · 35–55 min · free
Nothing on this page gives anything away — it knows whether the case was closed and nothing about how.