Johannesburg - Former deputy president Jacob Zuma is to be slapped with another charge of tax evasion involving about R2m.

And Scorpions investigators believe they might have found the missing link in what could explain the flow of money from Thales/Thomson to Zuma.

This comes as Zuma supporters led by Cosatu intensified their campaign to have all charges against Zuma dropped.

Cosatu has upped the stakes in the battle by demanding the re-opening of the entire R43bn arms deal probe.

The union federation believes that Zuma is being made a sacrificial lamb and that other senior government leaders need to be investigated.

President Thabo Mbeki and his cabinet members have maintained that there were no irregularities in the awarding of the main arms deal contracts.

City Press revealed on Sunday that the investigation regarding the contravention of the Income Tax Act "was recently declared".

The investigators, it is understood, wanted to pin Zuma down on R1.2 million allegedly received as a bribe from convicted fraudster Schabir Shaik, and payments totalling R656 000 received from Namibian expatriate Jurgen Kogl.

Other payments looked at include the R140 000 paid by Mpumalanga businesswoman Nora Fakude-Nkuna for Zuma's R900 000 Nkandla traditional home and another payment of R181 756 in bond repayments by Durban businessman Vivian Reddy.

"It is obvious from all the above that the payments were corrupt benefits bestowed upon Zuma in expectation of a quid pro quo. In this sense they were income earned by Zuma.

"There is a reasonable suspicion that they were not declared to South African Revenue Services (SARS) as required or to Parliament, particularly as it was Shaik's defence that his payments to Zuma were loans," said senior special investigator Johan du Plooy in an affidavit submitted to the Pretoria High Court.

The investigators are understood to be looking at possibilities of charging some of Zuma's funders who could have contravened the Companies Act, in the same way they charged Shaik.

With acknowledgements to Jimmy Seepe and the City Press.