I'd like to hear from you about what i have found out.
In our place they open a company who will accept investments which they guaranteed 400% interest for 1 month. I have found out that they do crypto trading. Is this usual to identify them as a scam?
The moment an "investment" company says "guaranteed", that's already a huge red flag. They'll probably show you some success stories as a proof of their legitimacy and entice you to invest as well but don't ever fall for it.