A form four candidate from Gesiasa Secondary School died on Monday minutes after writing the Mathematics paper.
Keith Mong'are, 17, collapsed and died on spot with efforts to resuscitate him hitting a snug, his father Joshua Ongaga confirmed.
The Monday morning incident sent shock waves across the neighborhood with hundreds trickling into the school compound to witness.
"My son has a heart problem and we have been taking him for medication, his last session being at The Mater hospital in Nairobi," Mr Ongaga said.
He added: "The heart problem developed from his days as an infant and for long, he has been under medication.
His body was moved to Kinara Hospital, formally Bwomboga Funeral Home, few kilometres from the institution which is located in Bosamaro ward.
Master Mong'are was among 192 students from the institution sitting for Kenya Certificate for Secondary Education.
Kenya National Examination Council chairman Prof George Magoha confirmed the incident and said investigations were underway.
"The examination started well and we only have two cases of death, one in Nyamira and another one in Murang'a," he said.
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