Strong circumstantial evidence == minister said “I'm not the sea captain. But I would think that you would notice that you're dragging an anchor behind you for hundreds of kilometers”.
So no evidence then at all. It's just speculation.
When “coincidences” like this percolate up to the general public, I think it is in fact noteworthy.
At certain odds, statistical likelihood is evidence
And then there's common sense. Something most people seems to lack.
As is usually the case, before a crime is investigated.
Hence investigations, good detectives, good hunches, etc.