SOLDIERX.COM Nobody Can Stop Information Insemination

I know I was hacked a few months ago
I have contacted authorities but they couldn't help because I don't have enough evidence

I think the evidence is in a secret facebook group( where they post my personal information they obtained)

I would like to get into the facebook account of the people and have a look and get evidence so the police could help me

I have thought of different ways but I was thinking the easiest way to get into a fb account would be a keylogger or something

The person has a website
he also has a closed(but almost everyone is allowed to join) group

My life is ruined by them and I desparately need help

Thanks in advance