Paul O'Sullivan, Jackie Selebi's chief accuser, has vowed to take legal action against the person identified as "Luciano" in secretly-taped conversations between former National Prosecuting Authority head Bulelani Ngcuka and ex-Scorpions boss Leonard McCarthy, once he has identified the individual.

Last week, acting National Director of Public Prosecutions Mokotedi Mpshe announced the case against the African National Congress president would be withdrawn.

While announcing the decision Mpshe read out transcripts of conversations between Ngcuka and McCarthy.

Mpshe said the two abused the NPA's legal process in deciding when to charge Zuma with corruption.

O'Sullivan claims Selebi was responsible for the tapes and that he handed the recordings to Zuma's legal team.

He also says he has no doubt that Selebi has more tapes referring to his prosecution.

In the transcripts, McCarthy had lengthy conversations with a private intelligence operative named "Luciano" in which he suggested there was political interference in the review of Selebi?s case.

O'Sullivan says he was working on identifying Luciano.

"At this moment in time I have a hypothesis which I?m working on. I've got a list of names and I've gone through them and crossed off the ones who I think it can't be and I'm left with about four or five names. I've got people working on it and I think when we do find out it will be very revealing."

Selebi will know on Tuesday whether he will go on trial or if the case against him will be withdrawn.

He is facing charges of corruption and defeating the ends of justice.