Top Scorpions investigator Gerda Ferreira, the woman who successfully prosecuted disgraced ANC parliamentary chief whip Tony Yengeni for lying to parliament, has resigned from the elite unit.

It is understood that Ferreira has accepted an offer to work for one of the country's top banking groups.

But Scorpions spokesman Sipho Ngwema said Ferreira's resignation had no sinister connotation and would not derail the Jacob Zuma probe.

Ngwema said today that "an arrangement had been reached" for Ferreira to continue with the investigation even after her departure date at the beginning of September if the case dragged on.

"There is also no link between the probe into the deputy president and her departure. She is leaving to pursue another career option," Ngwema said.

The Scorpions investigation centres on an alleged R500 000 bribe paid to Zuma by a French firm involved in the multibillion rand arms deal, and also focuses on Zuma's relationship with his financial adviser, Schabir Shaik.

The investigation into the multibillion-rand arms deal was boosted when the Scorpions turned their sights on Shaik, a Durban businessman.

The answers they wanted included what he knew about allegations that Zuma had solicited a bribe of R500 000 a year to protect, Thales, one of the companies involved in the arms deal during the multi-agency arms deal probe.

Durban High Court judge Ron McLaren ruled recently that Shaik, facing charges related to the theft of confidential state documents, must respond to the Scorpions summons and answer the questions.

Shaik was allegedly present at a meeting at which Zuma allegedly solicited the protection bribe from Thales, formerly known as Thompson CSF.

Thales and its South African subsidiary African Defence Systems (ADS) were part of the group that won contracts in the arms deal.

Shaik, who is allegedly a shareholder of Thales, a director of ADS and a director of Nkobi holdings, has been questioned about "negotiations, requests, correspondence, meetings or other arrangements concerning the payment of money or the granting of other benefits by any of the persons or entities mentioned aboveto any of the other persons or entities mentioned above".

Shaik could not be reached for comment.

Group Political Editor, John Battersby, reports that the Scorpions could become a specialised unit of the police to resolve the institutional tension between them.

President Thabo Mbeki said that while there was no plan to dissolve the Scorpions, the structural tension between them and the police would have be to addressed.

With acknowledgements to Johan Schronen and the Cape Argus.