The body of activist Caroline Mwatha who went missing on February 6 was on Tuesday afternoon found at the City Mortuary in Nairobi.
Detectives handling the case said one one woman who owns a clinic was arrested over the murder of the activist.
Police sources indicate Ms Mwatha was seen at the said clinic before she went missing only for her to be found dead at the city mortuary.
She was the founder member of Dandora Community Justice Center and was in the forefront in fighting for the rights of the citizens, specifically against extrajudicial killings.
Earlier, Nairobi Governor Mike Sonko had offered Sh300,000 for anyone who would have provided information that could have led to the finding of the woman.
Her husband Joshua Ochieng, a business man in Dubai, is also said to be in fear for his life.
Ochieng had ealier revealed he called his wife the very same day she went missing but she was not picking his calls.