Police in Murang'a are searching for a woman suspected of stabbing her two-year-old son to death with a kitchen knife.
The 21-year-old mother of two sons is also said to have seriously injured the other child, aged four, before she attempted to take her own life.
The killing occurred on Sunday afternoon in Kianjogu village, said Murang'a County Criminal Investigations Officer Daniel Kandie.
"The young mother had reported to her home village during the Christmas season. She was working as a house help in Kiria-ini, leaving her two children under the care of their grandmother," Mr Kandie said.
Neighbours told Nation.Africa that the young mother did not look and was withdrawn during the holidays.
Lying in pools of blood
"She used to be a jovial woman but she had changed. She looked disturbed and kept to herself. She had suddenly become sullen and did not appear to be in a hurry to go back to work," said Jacinta Gathoni, a neighbour.
Villagers said they did not hear any commotion in the house where she is suspected to have attacked the minors.
"Their grandmother was away...we only learnt of the tragedy when she came back and screamed upon stumbling on the children lying in pools of blood," she added.
A preliminary police report said a rope was hanging from the ceiling of the sitting room, where the two brothers lay unconscious.
"It is perceived the mother intended to take her own life after stabbing them. But it appears she had a change of heart and decided to run away from the scene," the report says.
The injured boy is hospitalised at Murang'a Level Five Hospital in critical condition while the body of the other boy was taken to the Muriranjas Hospital mortuary.
Mr Kandie said the mother was being sought as the prime suspect.