Police in Kisii are yet to trace a female cleric who went missing from Bonchari, in Kisii a month ago.
Area residents and security chiefs suspect foul play in the abduction even as Kisii County Police Commander Abdi Hassan said the search has been intensified.
Last week, several houses belonging to three suspects were set ablaze.
Interior Cabinet Secretary Fred Matiangi said the officers under the Directorate of Criminal Investigations officer in Kisii will lead the probe.
Dr Matiang'i urged residents to co-operate with authorities as investigations into the incident intensify.
“We urge that anybody with any information to freely and willingly share it with the security agencies so that this incident is concluded once and for all,” the CS Matiang'i said on Saturday.
He was speaking at Mwongori, Borabu in Nyamira County during a tour of the area.
The pastor identified as Ms Esther Bosibori is said to have been abducted from her house at night early March by unknown people.
For weeks, police have combed the villages, rivers and tunnels in the Bonchari sub-county in frantic search for the woman.
Dr Matiangi said the chiefs in the locality should also be ready to provide answers on circumstances surrounding the abduction.
“Any administrator not up to his task should consider relinquishing his post to allow those willing and competent to be employed,” Dr Matiangi warned.