According to this BBC article [bbc.co.uk], a man (in the loosest sense of the word) was jailed for 18 weeks for 4 cases of trolling where the subject of his twisted posts were teenagers who had recently died.
I know how harmful this is due to losing my closest friend to suicide 5 years ago and hearing unsubstantiated garbage about him, his family were having a hard enough time as it was.
Got what he deserved, I hope the people in the jail he is sent to get to know what he has done.
The penalty isn't harsh enough, imho. Not prison time, but should be some sort of social work with the disadvantaged, for example. It'd also be worth an assessment of the mental status of the individual as, surely, it's not normal for someone of that age to act in such a way.