Johannesburg, May 26 (IANS): More than 28,000 people have been defrauded of a total of over $83 million with promise of higher interests in South Africa, police said, as they are investigating the case.

The police said Bitcaw trading company, commonly known as BTC Global, invited people to invest money and promised 2 per cent interest per day, 14 per cent per week and ultimately 50 per cent per month, Xinhua reported.

South Africa's serious economic offences unit is currently investigating the case.

"This may prove to be the tip of the iceberg with potentially thousands more yet to discover they have lost money," said acting National Head of the Directorate for Priority Crime Investigation Yolisa Matakata.

"These is a timely reminder that unregulated, unusual investments at home or abroad come with a high risk that people could lose all their hard-earned pension and other saving," said Matakata.

Matakata said some of the investors got paid according to the agreement and the company failed to pay others and suddenly stopped disbursing funds.

The police invited people who invested in the company to come forward and promised to keep their details confidential.

Matakata said, "Despite the setback we want to assure the affected individuals that we are investigating the matter but due to the large volumes, it will take time to conclude."

The South African Reserve Bank has in the past warned people not to invest in pyramid schemes which are illegal.

The South African Banking Risk Information Center, an association of the banks has also warned people not to invest in the schemes which are "too good to be true."