A Kenyan lawyer went on trial on Tuesday accused of bribing and intimidating witnesses in the failed International Criminal Court (ICC) case against Deputy President William Ruto.
Paul Gicheru led an "egregious and damaging" witness tampering scheme that made it impossible to pursue allegations against Ruto over post-election violence in Kenya in 2007-2008, prosecutors said.
Prosecutors allege that Gicheru paid bribes of up to one million Kenyan shillings ($9,200, 7,800 euros) and threatened the safety of ICC witnesses, one of them at gunpoint.
Gicheru denies the allegations. "For the record, I plead not guilty," he told the Hague-based court.
ICC deputy prosecutor James Stewart said Gicheru's trial was crucial to protect the "integrity" of the world's only permanent war crimes tribunal, which was set up in 2002.
"Those who would seek to undermine the court's ability to provide redress for victims of mass atrocities cannot be allowed to prevail," Stewart told judges.
Gicheru had "managed and coordinated a scheme to identify, locate and corruptly influence" witnesses throughout the ICC trial of Ruto and co-defendant Joshua Sang, which collapsed in 2016, he said.
"This was done through a combination of bribery and intimidation," said Stewart.
Four "vital" prosecution witnesses had recanted their testimony as a result of Gicheru's actions. Another two witnesses reported him to the ICC, Stewart said.
Prosecutors noted that of the individuals "caught up in the witness tampering scheme", one witness had died and another had disappeared -- although there were no allegations that Gicheru had been directly linked to their fate.
Prosecution lawyer Anton Steynberg said the "wide ranging and concerted scheme" involved witnesses being offered large sums of money not to testify to the ICC.
Gicheru had set up meetings and then paid bribes in installments of hundreds of thousands of shillings, he said.
One witness was told that they would "now be safe" after accepting the bribe, Steynberg said.
The ICC also launched a case against Ruto's boss, Kenyan President Uhuru Kenyatta, over the post-electoral violence. That too collapsed, in 2014.
The disputed 2007 vote in Kenya fuelled tribal violence involving bows, arrows and machetes that left 1,100 people dead.
The ICC's new chief prosecutor, Karim Khan, has recused himself from all Kenya cases as he was Ruto's lawyer during his trial.