I don't think they can get their money back because they are not from the US, and with everything like this it will be a very long process.
Chances are a bulk of the money in Bitconnect is in cryptos, for any agency to get the money they will need to get the private keys of the wallet, if the assets are held in exchanges then the process will be slightly simpler but if they are in more harder to access exchanges then this is going to be very difficult. Consider your money burned if you invested in BitConnect.