Police in Siakago, Embu County, are holding a 40-year-old woman on suspicion of stealing a child.
The woman was arrested by a chief after failing to explain how she got a three-month-old baby boy and yet she had not been pregnant.
Children’s Officer Jane Kinuthia presented the boy in a court in Siakago as a child in need of care and protection.
At the court, the woman claimed that her husband found the child abandoned near a sawmill in Murang'a and took him home.
The woman objected to the child being taken to a children's home, saying she has been married for 15 years and had no children.
Ms Kinuthia said authorities were investigating the case and treating the incident as a case of child trafficking.
She appealed to people who may have lost a boy aged three months to report to the police.
(Editing by Beatrice Obwocha)