From reading the news story, it is obvious that teenage troublemakers are more likely culprits. However, the news story makes the sadly too-common error of thinking that witches are devil worshippers who like to go about desecrating Christian sites. It also makes the mistake of thinking that witches are frequently children.
I do hope plenty of people comment on the North Wales Weekly News site to point out that witches are pagans, they do not worship the Devil, which is a Christian concept. Witches have no interest in vandalising churches and are usually pretty law-abiding. And, most importantly, covens certainly don't initiate children - most have a strict over-18 policy.