Details of how 1,205 Form Four candidates cheated during last year's national examinations have been released.
A report by the Kenya National Examinations Council shows that most candidates, whose results were cancelled, were found with mobile phones.
The report came as Knec chairman George Magoha told the 2018 Kenya Certificate of Secondary Education test candidates that there will be no room for cheating.
In a TV interview, Prof Magoha said some groups have begun collecting money from headteachers, candidates and parents, promising to sell to them examination papers.
"Some school leaders...are collecting money from children, promising to give them an examination they will not see. We have ensured that there will be no leakage," he said.
In its report, Knec says it constituted a team of 36 subject specialists to scrutinise the answer scripts in the affected subjects.
The investigators were divided in groups of seven subject specialists.
These were a subject chief examiner, four examiners with a 10-year experience randomly selected, a Knec subject officer and one Kenya Institute of Curriculum Development subject specialist.
The study also shows that candidates produced identical responses to questions, meaning there was collusion.
In one school in the northeast, all the 70 students had a similar but wrong answer in English paper 2.
In another question, 69 candidates at the centre had a similar wrong response while another cancelled the correct answer and replaced it with the wrong one.
In physics paper 1, all nine candidates presented similar incomplete curves for the graph of potential energy against time, the report added.
In another school in eastern Kenya, 96 of the 97 candidates sitting the chemistry practicals paper had their results revoked.
The candidates presented similar answers to most questions.
In one instance, a candidate who had initially given the right answer cancelled it and wrote the wrong one.
In a school in the Rift Valley, all 162 candidates cheated in English paper 2 as they gave similar responses to one question.
A scrutiny of the candidates' scripts by subject specialists showed they colluded.
"It is highly improbable for candidates to have similar and even identical responses to higher order questions that require interpretation and inference," the report says.
"A good number of candidates cancelled or erased own responses and replaced them with those that were common. Some even cancelled correct responses."
At the same school, 20 candidates had their physics paper 1 results cancelled.
In one question, 18 candidates presented similar incorrect response thus: "The drop is spherical in shape."
However, the response did not require characteristics of the drops.
ENGLISH PAPER 2
In one Rift Valley school, the 320 candidates cheated in English Paper 2. In one question, most used similar words, attracting suspicion from markers.
"It is worth noting that almost all the candidates used the word "provocative/provoking", which is not commonly used at the level," the report reads.
In the same centre, 319 of the 320 students cheated in biology paper 2, with seven giving the correct identical responses word for word.
Fifteen candidates presented an identical though wrong response.
At another school in the Rift Valley, candidates cheated in history and government, with 22 giving a similar incorrect response. Another six gave incorrect responses using the same word.
At an examination centre in western Kenya, 189 out of 190 candidates cheated in the biology paper, presenting similar incorrect responses to a question.
"The responses were far-fetched, a clear indication that the candidates accessed the answers from a common source," the report says.
In a school in Nyanza, 191 out of 205 students cheated in English paper 2.
In one question, candidates had a similar response: "Azdak has just surrendered to the police for allowing the grand duke to escape".
"Note that the word 'police' is not used anywhere yet most candidates used it instead of the term 'ironshirts' that appears in the text," the report adds.
Schools whose results were cancelled include Chalbi Boys, Barazani Girls, St Cecilia Girls Chepareria, Ortum, Koelel, Tenges, Chebuyusi Boys, Mokubo and Towfiq.
The council said the centres were involved in various forms of examination irregularities.