The lead investigator in the R2-billion Kusile Power Station corruption case has backtracked on his testimony that two German nationals accused in the matter will not be extradited to stand trial.

On Thursday, the investigating officer continued to be cross-examined by the state.

He is on the stand as a witness in an inquiry at the Middleburg Specialised Commercial Crimes Court in Mpumalanga to determine if there were any unreasonable delays in the case against former Eskom executive Matshela Koko and his co-accused.

The officer cannot be named by court order.

Koko and his co-accused, including his wife, Mosima; stepdaughters, Koketso Aren and Thato Choma; former SA Local Government Association CEO Thabo Mokwena; lawyer Johannes Coetzee and Watson Seswai; senior Eskom project director Hlupheka Sithole; German citizens Sunil Vip and Markus Bruegmann; Gopal Kambi; Lesetsa Mutchinya; and companies linked to some of them were charged in October last year.

The investigating officer told the court during his last appearance on 1 November that he was unaware of any application for the extradition of Vip and Bruegmann.

Continuing with his cross-examination, Advocate Shaun Abrahams, counsel for Mokwena and his two companies, asked the officer when a decision not to extradite the two Germans was made.

In response, the officer claimed he never said that. He told Abrahams there was a misunderstanding, as the previous Afrikaans interpreter didn't convey his response correctly.

However, Magistrate Stanley Jacobs stepped in and told the officer that there was no misunderstanding.

"The court understands Afrikaans. That is what you said. I'm not referring to the interpretation. I'm referring to what you said. That is what my notes reflect," Jacobs said.

The investigator then conceded and said there was no extradition process underway, but said that didn't mean the two would not be prosecuted.

He said Interpol Red Notices – requests to law enforcement worldwide to locate and provisionally arrest a person pending extradition, surrender or similar legal action – had been issued, and should the two travel to other countries, they would be arrested and brought to South Africa to stand trial.