Turning up at an address should not even be worth considering unless he has agreed to meet you. You don't know if it will be the right person and you put yourself at risk in multiple ways.

This is one for the police first, then lawyers if necessary.

I would say enough of you have been scammed to be able to put together a few btc for a lawyer and then a barrister -if- it becomes necessary and worthwhile, ie the money still exists and the CPS don't do what is required. This is beyond my legal knowledge unfortunately.

My suspicion is that projects ran up debts through gambling or bad trades, perhaps to bad people hence the recent rush for money.