Either
he is attacking you by means of a so called Billiardstroke. It is an
indirect stroke manipulating a third person against you, for instance like
Iago in Shakespeare's Othello.
Or he
makes use of a weakness of his object, a soft spot, a compromising situation, blowing up
guilt: this is the thrust against the Achilles Heel, for instance you can find it in
the Profumo-Affair.
The
third stratagem is the alliance of several persons to attack someone, some
kinds of Conspiracy, for instance the Philistines plot with Delilah
against Samson.
You
can find more of this daily experience in life if you read