There are several ways to kill a school teacher
You can put him in a prison
For teaching false doctrines.
To do this properly you require a copy of "The Origins of the Species"
A bible belt, some religious fanatics
A bad lawyer, a fixed jury
And 26 years with nothing to do.

Or you can offer him hemlock
Crushed and ground in a glass of wine
Drunk by the victim by choice
But for this you need an "Academia"
A philosopher, some corrupted youths
At least two tautologies, several sophists
And a cynical playwright to mock them.

Dispensing with legalities you may, if the Pope allows,
Denounce him. But then you need to refute his thesis
(all eighty nine of them) a church door, some nails
More nails, a diet of Worms, a colloquy at Rome
And some rich catholics in purgatory.

In an age of television you may
Replace him with a teaching machine and programmes
All you then require is a behavioral scientist
Some bells, a salivating dog, some white rats
And a solipsism as a working hypothesis

There are, as I began, several ways to kill a teacher
Simpler direct and much more neat is to
 make them teach to ofsted standards and leave them there.