I would recommend members to pay money into the sellers bank account incase you are doubtful of them.
Most probably the scammer wont be willing to do that and even if he does,legal action (if taken) will be much easier to do.
As @PunkX 75 said, paying advance to a member with 0 feedback(let alone who joined a day before) is a bad idea.
Even if you pay him, the least you should have done is check the gpu running via a video call.