The incident occurred outside a pub where the officer used his gun during a confrontation where the deceased and several other people were also present.
Keiyo South DCI boss Samwel Otieno confirmed that 25-year-old Philemon Salwa Mugambi died at the Moi Referral Hospital where he was rushed after he was shot by AP Sergent Justus Kirimi attached to Railways AP camp near Flax centre.
“We have arrested the officer and taken the gun from him," Otieno said.
He said the officer used a pistol to shoot the victim on the head. Witnesses claimed that the officer was in the pub when he was called out by the deceased.
A confrontation ensued between the officer and Mugambi as other people tried to separate the two.
They were quarrelling over the woman who was present.
“In the argument, the officer drew his gun and shot the young man. The officer was also injured in the confrontation but was treated and discharged," Otieno said.
The woman and several other people present have recorded statements.
Otieno said they have launched investigations into the incident before the officer is taken to court.
Elgeyo Marakwet County Police Commander Kennedy Kimani cautioned both members of the public and police not to take the law into their hands whenever they have disputes.
“We will find out what exactly happened and if the officer is found to have misused the gun then proper action will be taken,” he added.