The hacker can sell those merits (or took merit to his accounts) or hacker can send merit randomly. If these accounts are connected then we would be able to tell undoubtedly that those are engaged with hacking or merit abusing.
It would be a huge co-incidence to have never received merits and then get 50 merits randomly from a hacked account.
Why would a hacker give away free merits (maximum allowable) to random accounts when they can sell them ?
I have strong suspicions that the accounts are either associated to the hacker or th merit was bought - either deserves red tagging.
Mr Felt got merits from a hacked account AND got trust from a different account with a hacking accusation against it.
Usually, it engaged with merit trading and/or sending merit to his/her own account. But sometime it may happen sothat we can concentrate on the merited person so that hacker can stay away. But as merited accounts are not high ranked that possibility is too low. There might have 5-10% chance to be random. If they trade those merit then it will be difficult to catch though we imagine they are engaged merit trading but if those are altered then we could tell 100% confidently. I will try to visit those profiles and try to get if there is any matching info.
Edit:
All merit has been sent within 6 minutes so there is more chance to alter account of the hacker.
All accounts received merit only from the hacked account.
They have not used any smerit. So, if they bought they could sell too. It is more chance to be altered of the hacker account.
Your mentioned 3 positive feedback was long ago in the meantime anyone's mind can be changed.