After discovering he was on a case of an alleged sex offender, a juror posted on Facebook: "Woooow I wasn't expecting to be in a jury Deciding a paedophile's fate, I've always wanted to F*** up a paedophile & now I'm within the law!"
After being dropped from the trial, Kasim Davey has been jailed for two months after being found guilty of contempt of court.
Another juror, Joseph Beard, was also found guilty of contempt by using the internet to research the case he was sitting on as a juror.
The Attorney General said: "Jurors who use the internet to research a case undermine justice.
"It creates a risk that the defendant will be convicted or acquitted, not on the evidence, but on unchallenged and untested material discovered by the juror.
"Equally, the case of Kasim Davey shows that jurors must follow the directions given to them by the trial judge not to discuss the case outside the jury room, including discussions and posts on the internet."