A group of armed men stormed a family Monday morning in Narok South, went straight to where a 13-year-old boy was and slashed him with a machete killing him.
The incident at Esimenwa village caused tension in the area which had experienced relative calm after the government sent a contingent of police officers to quell clashes between two communities.
In the morning raid, a 70-year-old granny and another 12-year-old kid were left with machete injuries.
They were rushed to Longisa Mission Hospital.
Residents said they fear there might be retaliatory attacks over the incident calling on the government to beef up security.
Area county commissioner said everything has been done to contain any situation.
"I wish to assure the public that security agents are alert to avert any violence. A team of security officers is already on the ground to pursue the attackers," George Natembeya, the commissioner, said.