POSTERN OF FATE Agatha Christie

'I wanted to see if there were any Jordans buried there.'
'Good gracious,' said Tommy. 'Are you still on that? Were you looking
for -'
'Well, Mary Jordan died. We know she died. We know because we had
a book that said she didn't die a natural death, but she'd still have to be
buried somewhere, wouldn't she?'
'Undeniably,' said Tommy, 'unless she was buried in this garden.'
'I don't think that's very likely,' said Tuppence, 'because I think that it
was only this boy or girl - it must have been a boy, I think - of course it
was a boy, his name was Alexander - and he obviously thought he'd
been rather clever in knowing that she'd not died a natural death. But
if he was the only person who'd made up his mind about that or who'd
discovered it - well, I mean, nobody else had, I suppose. I mean, she
just died and was buried and nobody said...'
'Nobody said there had been foul play,' suggested Thomas.
'That sort of thing, yes. Poisoned or knocked on the head or pushed off
a cliff or run over by a car or - oh, lots of ways I can think of.'
'I'm sure you can,' said Tommy. 'Only good thing about you, Tuppence,
is that at least you have a kindly heart. You wouldn't put them into
execution just for fun.'