Indeed uncanny. Boat tethered to tree in secluded part of broads. Daughter unharmed, seemingly not distraught, boat overdue. Bodies of both parents found in the water, no alarm given. You could say alarm not possible from that marshland, what about mobile phone every kid has? Out of range?
Imagination can run wild in these situations – my first thought was not some pact of the adults or even an accident but more along these lines. No justification for thinking that of course. Just that 13 is quite sentient, the outside influences on kids now are frightening.
The explanation doing the rounds of the local area is that one parent went off somehow and the other followed later when he didn’t return. Daughter was told to wait. Can’t see it because there was no path, it was secluded and marshy – they’d have moored where a path led away from.