The Kenya Human Rights Commission has called on police to probe the death of ICC suspect Paul Gicheru.
Gicheru was found dead on Monday at his Karen home in Nairobi.
In a statement on Tuesday, KHRC said police should take action as the details of his death unfold.
"While the full details surrounding this death are still emerging, we remain concerned with the shocking news of the untimely death of Kenyan lawyer Paul Gicheru who was facing charges of witness interference at the International Criminal Court," the statement read.
"We call on the Directorate of Criminal Investigations and the National Police Service to conduct swift and conclusive investigations into the death of Paul Gicheru."
Police said the cause of his death is yet to be established.
"He had late lunch and felt unwell and went to bed but he did not wake up," police said.
Police said he was found unresponsive at about 7 pm.
"His son too collapsed and was taken to Karen hospital in stable condition," police added.
Gicheru was accused of offences against the administration of justice by corruptly influencing witnesses of the Court.
He allegedly bribed witnesses to either recant their testimonies or refuse to testify in the crimes against humanity case that faced President William Ruto and former journalist Joshua Sang.
Cases against the two were officially terminated in April 2016 after they were found to have no case to answer.
