A mentally challenged girl from Bus Park Makongeni area in Kiambu, on Saturday morning gave birth on her own in an abandoned stall.
The girl was living under her custodian's care while she was pregnant.
Residents were woken up by wails of a girl in agony and rushed to the scene to find her having safely delivered a bouncing baby boy.
Good samaritans donated clothes so she could cover the newborn and took them to a nearby clinic.
It is claimed that she was violated and impregnanted by an unkown person.
The area MCA Mary Hussein arrived later on and took the young mother to a health centre for observation where she would continue to receive post-natal care.
"Such people should be dealt with accordingly to avoid a reoccurrence. They must be hunted down," she said.
She noted that cases of rape on mentally challenged girls have happened in the past with the offenders managing to get away with it.
