reading that/watching the embedded news report it sounds to me like the individual being charged is being made a scapegoat.
I would be less cynical if 2 or 3 of the others involved had also been charged with some sort of offence.
As for the sheriff's comments that he had not seen all the video previously well, maybe he should have reviewed it before commenting initially.
Nah. something smells and it ain't my socks
All three officers have been suspended, and that was a while ago (July). Article here: http://www.dailymail.co.uk/news/article-4744588/Three-cops-suspended-repeatedly-tasering-teen.html
The charges against one officer are in addition to the suspension and one or both of the other officers could also be charged at any point going forward. 'The wheels of justice grind slowly but exceedingly fine'.
-unknown
I have no idea how this works in the UK but this criminal action (the officer being charged) will hugely fuel the civil lawsuit already launched by the victim, both as far as the likelihood the victim will win as well as increasing damages.
Brian