Two teenage girls sustained serious injuries in a forced circumcision at Kaptul village in Marakwet East on Tuesday.
Kimuren assistant chief Paul Chepkirui said the girls' parents and a traditional circumciser went into hiding but police launched a search.
He said the girls aged 14 and 15, who did their KCPE examinations a week ago, were taken to hospital.
The parents are said to have forced the girls to undergo the illegal cut.
"The case is being handled at the office of the assistant county commissioner. We will take action" Chepkirui said.
"We have presented a report to police who are now handling the matter."
Chepkirui said the girls resisted the forced circumcision but were overpowered.
"FGM is outlawed so those who did it will face the law as required," the chief noted.
The case has been referred to Elgeyo county commissioner Fredrick Ndambuki.
POLICE ON HIGH ALERT
Marakwet East deputy commissioner Stephen Sangolo warned circumcisers and supporters of the practice of serious consequences.
He noted the culprits in this case are known so police will soon apprehend them and update the public.
Gender CS Sicily Kariuki chats with a reformed female circumciser in Tot, Marakwet East, in January 2016. /STEPHEN RUTTO
Sangolo said officers have taken measures to ensure FGM does not take place in villages, especially during the season.
"Security agencies will be on high alert to prevent any other incident."
Hundreds of girls are normally lined up for the cut during December holidays.
Chiefs have been directed to conduct a crackdown on those involved since traditional astrologists gave the green light last week.
In November and December 2015, at least 1,200 girls were illegally circumcised in Marakwet East.
A pupil of Chebilil Primary School in Kerio Valley was reported dead after the rite.
In September, an anti-FGM organisation kicked off a sensitisation drive in the valley where the practice is rampant.
Marakwet Girls Foundation founder Jepchumba Kilimo said young girls in parts of Marakwet and Keiyo are the targets.
Former MP Linah Kilimo, who has been leading the fight against female genital mutilation, condemned the incident.
"Those involved must be punished as per the law to serve as an example to others," she said.