Police said the governor will be charged in a Nairobi court on Monday as a person of interest in the Rongo university student's killing.
He was grilled for hours by officers from the Directorate of Criminal Investigations at the Kiambu headquarters.
The county chief has denied any link to the murder of the 26-year-old student but admitted they were lovers.
Last week, Obado told the police in Kisumu that he too was interested in knowing Sharon’s killers.
His lawyer Cliff Ombeta has maintained that his client is innocent and has told the police what he knew about the case.
Sharon's body was on September 5 found dumped in a thicket near Kodera forest after her abduction.
She was in the company of Nation journalist Barack Oduor who says he escaped from the hands of the abductors.
-The Star