> Maybe they are waiting for you to deposit more bitcoin into that address, or maybe they are waiting to collect more private keys before exploiting them all at

> Maybe they are waiting for you to deposit more bitcoin into that address, or maybe they are waiting to collect more private keys before exploiting them all at the same time, or maybe they... why speculate? Well, from a criminal's point of view, I don't see the upside in waiting. The owner of the coins could move them at any time, and then your loot is gone for good. I think it's safe to assume that if someone else has possession of your private keys, your addresses will be drained immediately.