Kiambu Governor Ferdinand Waititu has been arrested by Ethics and Anti-Corruption (EACC) officers.
The governor was arrested in his Runda home after the officers raided his other home in Garden Estate and a house which is resided by his daughter.
He was then interrogated for six hours before the detectives took him in for further questioning.
The officers were searching for vital documents as the EACC steps up their graft probe over audit queries in Kiambu county.
Officials said apart from Waititu, 15 other county officials were targeted.
Waititu has been on the radar of EACC over claims of graft and his sudden wealth in the city.