They won't come back:

this is the BTC addres they sent payments from:

https://blockchain.info/address/1PjNgsDKCMWBMe8s9RXSTU8jKPMY7nQ3pz

As everyone can see this address is cleared, I counted more than 2000 BTCs that was disappeared in various group transactions.
I followed the first -400 BTCs until I reached this address:

https://blockchain.info/address/15bNwqC25FtG6b3igwaT9kapma1keq9mj6

This one contains almost 5750 bitcoins.

So you could say, this is their savings account...