Mandera Senator Billow Kerrow was on Thursday morning arrested at the Wilson Airport, as soon as he landed from Mandera.
Kerrow arrived at the airport only to find officers waiting for him, afterwhich he was seized and driven to the Directorate of Criminal Investigations Headquarters.
Reports indicate that five other MPs were also arrested following accusations they made, that the government was behind extrajudicial killings in Mandera.
Senator Kerrow had claimed that government security agencies were behind the disappearances and killings of Mandera residents, in the wake of reports that a mass grave was discovered in the county with twelve bodies.
Interior Cabinet Secretary Joseph Nkaissery demanded an apology from the legislator, after government confirmed that upon excavation no more bodies were retrieved, apart from that of a woman.
The Senator was arrested even after complying with Nkaissery's order - to make an apology before Thursday.