Security agencies are investigating the circumstances in which 10 candidates from Milimani Secondary School in Naivasha failed to sit the KCSE papers despite having registered.
Sources at the institution told the Nation that some of the students registered for the Kenya Certificate of Secondary Examination (KCSE) and left soon after never to return to school.
Other candidates missing their exams are said to have relocated with their parents from Naivasha.
"Majority of affected are those whose parents were working in several flower farms located within the Naivasha sub-county but were transferred or left for their rural homes," added the source.
Those missing out are among the 264 candidates registered to sit the examination at the Naivasha-based day school.
Speaking on the issue, Basic Education Principal Secretary Dr Belio Kipsang said Monday that the matter was under investigations.
"We have already picked it up, with the probe ongoing and we shall be able to establish what really transpired," he said.
"I don't want to comment further than that, but am I made to understand that some of the parents worked in flower farms and have since gone back to their rural homes," added Dr Kipsang.
Naivasha deputy county commissioner Mbogo Mathioya said one of the missing students had sat the papers on the first day of exams but failed to turn up for the subsequent papers.
However, Dr Kipsang said no major incident has been flagged at the school since the start of the examinations.
"We have had few issues in Kisii and Nairobi mainly within the private sector especially for privately registered candidates," said the PS.
He dispelled claims that some candidates were affected while sitting the Chemistry practical test.
"These are the same chemicals that they have been using in their normal teaching processes," he said.
He later visited Naivasha and Milimani secondary schools.