The International Criminal Court's prosecutor said on Wednesday he was happy for Libya rather than the Hague to try Muammar Gaddafi's son Saif al-Islam but the country's ex-intelligence chief was still at large.

Luis Moreno-Ocampo's remarks make it more likely Saif al-Islam will be tried by a Libyan court, where he faces the death penalty, even though the final decision lies with ICC judges rather than Moreno-Ocampo himself.

Moreno-Ocampo said he did not need to know that a Libyan trial would be fully fair, he simply wanted to be sure that it would not be a whitewash for Saif al-Islam, whom the ICC has indicted for crimes against humanity.

My standard, the standard of the ICC, is that it has to be a judicial process that is not organised to shield the suspect. That's it, that's it, Moreno-Ocampo told reporters during a visit to Tripoli following Saif al-Islam's weekend capture.

He later told Reuters: I don't think they are trying to shield Saif al-Islam Gaddafi here. I have no evidence of that.

Fighters from the Western Mountain town of Zintan caught Saif al-Islam in the southern desert on Saturday and flew him to their stronghold, where he is being held pending a handover to the Libyan government, which has not yet taken office.

The day after Saif al-Islam was found, senior National Transitional Council (NTC) officials said Gaddafi's former intelligence chief, Abdullah al-Senussi, had also been captured in the same desert region.

Of the three Libyans for whom the ICC had issued an arrest warrant, Gaddafi, Saif al-Islam and Senussi, the former spy chief was the last one still at large, since Gaddafi was killed shortly after his capture a month ago.

But Moreno-Ocampo said it seemed Senussi had not in fact been caught, reinforcing doubts that had grown since the prime minister designate, Abdurrahim El-Keib, said on Monday he needed to verify whether Senussi had indeed been captured.

I understand he has not been arrested, Moreno-Ocampo told Reuters, adding: I have no better information than you.

The head of the NTC, Mustafa Abdel Jalil, later appeared to confirm that Senussi was still free, telling reporters three days after the alleged capture: I do not have any confirmation of the arrest of Abdullah al-Senussi.

HOPE FOR THE BEST

Jalil and other Libyan officials are adamant that their country's courts can give Saif al-Islam and Senussi a fair trial despite concerns about the solidity of Libya's institutions after 42 years of dictatorship and a bloody civil war.

Human rights groups and some Western leaders had called on Libya to hand over Saif al-Islam to the global court, saying Gaddafi's son might not get a fair trial in his home country.

Moreno-Ocampo said that while he hoped for the best, he was happy to step aside as long as Saif al-Islam was prosecuted vigorously in Libya.

I hope they do a fair trial. My point is that we are not a system to monitor fair trials. We are a system to ensure no impunity, he said.

A legal expert at New York-based campaign group Human Rights Watch said it was up to the ICC's judges, not Moreno-Ocampo, to decide whether Saif al-Islam should be handed over to the Hague.

At the end of the day, this is not a prosecutorial decision, this is a judicial decision made by the ICC judges, Richard Dicker said.

What the judges will look at is the ability and the willingness to conduct a trial in Libya, and they will make their decision based on those two standards, he said, adding that Libya's ability to conduct the trial was the issue here.

While Saif al-Islam has not been charged in Libya yet, he would likely face multiple charges of murder over deaths that occurred during this year's revolution alone. The harshest sentence the ICC can impose is life in prison.

The provisional government, which was announced on Tuesday evening, faces a vast task in guiding the country towards democracy, with elections to a constituent assembly due in the middle of next year.

Moreno-Ocampo said he understood the importance of holding Saif al-Islam's trial in Libya as the country emerges from Gaddafi's long rule and the bloodshed involved in ending it.

The point is that for Libya, and I respect that, it is very important to do the cases in Libya. This is a right and I have nothing to say. I'm not competing for the case, he said.

Murder is murder, prosecution is a prosecution, I hope the Libyans can find a way to do it but that's why we're discussing modalities. Maybe for a few months, for some months, we'll keep working together.

(Additional reporting by Christian Lowe and Marie-Louise Gumuchian; Writing by Francois Murphy; Editing by David Stamp)