This is one of those things.
People often do not see what is there, instead the story in their head is concocted from a string of automated this-means-thats.

It is interesting that nosy neighbors often fall into this.
The assumption fly, with only a smidgen of evidence.

However, real crimes are rarely anything out of the ordinary.
The only way to know the difference between a burglar and a tenant is to know the people by sight.
And, 9 times out of 10, it was just a salesman or a friend coming to visit.

This is also one of the reasons why police are almost completely ineffective at solving crimes.
It is also the reason why people like Sherlock Holmes is so fascinating, when in actuality if anyone made those kinds of leaps of logic, they would be completely wrong. Its only by the writer knowing everything, that Holmes is right so much.