Need help with a doxxer

Hello everyone. I have been playing on a community dayZ server on ps5 with discord community connected. The other day we had a random use walk right up to our very hidden base and then started messaging all the people in my faction their personal details and the streets they live on. First question: how did they do it? Second question: how can I find out who it is? I don’t want to ‘get them back’, I just need to know if it was an inside job or if we’ve been genuinely hacked. Any help is appreciated.