However in this case they are likely to be connected and then they will come up with an excuse of "thats my brother/sister/My Dog/Neighbor's Cat" and so on.
as @Awaklara said. all three have similarities on social media accounts. but that's still not enough to prove the connection of the three.
Just inform BrainBoss about this and they will take care of it.
I already told the manager. I guess the manager might be able to see which account is real and the other account is cheating.
This data is raw and there is no guarantee that they (3 accounts) are the same person. it's just that the activity pattern by @walton and @voldamorVc is quite strange. like using other people's data too.
With the evidence, I don't think proving all three accounts of the same person is enough.
the most probable and certain is the use of other people's data to register for the rewards program.