According to the article the campaign is not doing a letter writing drive or anything like that at the moment as they fear that it could have a more negative than positive effect. They are asking for donations for his legal defense, or query on Veronza's website as to how else people could support.
One thing would be just to make people aware of the issue... spread the information, whether posting it on more websites, putting out posters and flyers, writing articles or letters to editors, etc.