Please read this article from Wales on Line, there are lots of articles on reliable sites such as the BBC, should you need more information.

Remember social media sites, such as Facebook, are opinion and not fact based so not always reliable.
Don’t be alarmed as there are no “local to us” concerns, but please be aware and monitor your child’s phone usage and content. Thank you. 
 

https://www.walesonline.co.uk/news/wales-news/warnings-issued-attempt-organise-fights-33511603.amp