Police say a Kenyan lawyer facing charges at the International Criminal Court of bribing and threatening prosecution witnesses in a past ICC case against Kenya’s recently elected president has been found dead.

Kenyan authorities have launched an investigation into the death of a lawyer accused of bribing and intimidating witnesses in the International Criminal Court (ICC) prosecution of President William Ruto, a police officer said Tuesday (September 28).

Paul Gicheru was accused by ICC prosecutors of setting up a "blatant and prejudicial" witness tampering scheme that made it impossible to pursue investigations against Mr. Ruto for his alleged role in Kenya's 2007-2008 post-election violence.

The lawyer, who was in his 50s, was found dead in his sleep on Monday night at his home in the Kenyan capital, Nairobi.

Mr. Gicheru's trial began in February in The Hague. Prosecutors have alleged that the lawyer bribed witnesses with up to one million Kenyan shillings (about 8,300 euros) and threatened others, including one at gunpoint.

Gicheru denied the charges, pleading not guilty before the ICC, based in The Hague.

"The information we have from his family is that he had a meal and then went to bed but did not wake up," a police officer who requested anonymity told the CNN.

"An investigation is underway to determine the cause of his death," the officer said, adding that Gicheru's son was taken to the hospital after complaining of stomach pains after sharing the same meal.

The Kenyan Human Rights Commission urged authorities on Twitter to "conduct a prompt and conclusive investigation" into the cause of death while expressing "concern over this shocking news."

Post-election violence between late 2007 and early 2008 left more than 1,300 people dead and 600,000 displaced in Kenya after the 2007 elections.

In 2014, the ICC dropped the case against then-President Uhuru Kenyatta on suspicion of crimes against humanity for his alleged role in the violence.

Then, in April 2016, it dismissed the case against Vice President William Ruto and radio presenter Joshua Arap Sang, who was prosecuted in the same case.

Gicheru had "set up a system to identify, locate and corruptly influence" witnesses in the trial against William Ruto and Joshua Sang, Deputy Prosecutor James Stewart said in 2016.

According to the prosecution, four key witnesses recanted their testimony as a result of actions taken by Mr. Gicheru.

William Ruto served for nine years as deputy president to head of state Uhuru Kenyatta before being elected president last August, defeating his rival Raila Odinga