The CBI had taken over the investigation on August 30 on the request of Karanataka government.

The CBI has filed its first chargesheet against IMA jewels promoter Mansoor Khan within eight days of probe for allegedly duping lakhs of people by promising them high returns using Islamic ways of investment, officials said on Monday.

In its report, the agency has charged Khan, the then managing director of I-Monetary Advisory (IMA) jewels, and 19 other accused -- seven company directors, five members, an auditor, a private person and five private group companies -- for alleged criminal conspiracy, cheating among other charges under the Indian Penal Code.

The officials said it is the first chargesheet in the scam before the special court in Bangalore and the agency will file further chargesheets as the investigation progresses.

The CBI had taken over investigation into the case on August 30 night on the request of the Karanataka government, routed through the Centre, they said.

Khan through his company IMA and its subsidiaries had allegedly duped over a lakh investors, mostly Muslims, promising high returns using Islamic ways of investment.

"It was alleged that the founder director (Khan) of group of entities based at Bangalore had illegally collected deposits from the public in the form of investments on various ponzi schemes such as monthly plan, education plan, marriage plan, etc., with a promise of getting high returns," a CBI spokesperson said.

He said it was further alleged that the accused persons widely propagated it through media, advertisements, religious scholars and others.

"It was also alleged that the money collected as deposits and investments was not used for any genuine business activity, instead the accused rotated a portion of deposits to distribute among the investors in the guise of profits," he said.

Most of the deposits were allegedly misappropriated by the accused for acquiring assets in names of family members, the agency has alleged.

The accused allegedly paid large bribes to public servants and others as protection money to carry out their illegal activities, the spokesperson said.

"After taking over the case, the CBI has formed a 12-Member Multi Disciplinary Investigation Team (MDIT) comprising its investigators who are being assisted by chartered accountants, forensic auditor, computer forensic experts and bankers," he said.