This is another scam within a scam. People who get scammed are approached by other (or the same?) scammers claiming they are officials trying to catch the scammers and get back the money for the victims.
However, those who claim to be officials, local or international, are scammers themselves and are often able to scam the victim for more money than the origial scam was worth.
Here is an example of a man in India who was scammed by a person claiming to be from the non-existent United Nations Intelligence Bureau.
THE UNITED NATION INTELLIGENT BUREAU
55 LODI ESTATE CHANAKA PURI
HE HAS CHEATED ME Rs.1,56,056/- (Rupees one lakh fifty six thousand and fifty six) for recovery of 35 lakhs from fraudsters.
I requested Dr.Billy Maxwell to remit my money Rs.1, 56, 056/-. But he switched off his mobile.
During the transaction, he has changed following 3 Vodafone Sim cards in his mobile.
ii) 07838034573 and
Also requested by E mail to remit money. But no response from him.
All payment receipts/proof were held with me. My mobile No. 09442082210.