At least seven people were arrested on Thursday evening in connection with the killing of 10 people in Banisa subcounty, Mandera.
They include the area chief, his assistant and a teacher whose identity is yet to be revealed.
Speaking to the Star on the phone, Northeastern regional commissioner Mohammed Birik said the two administrators were arrested for "sleeping on the job".
Birik added that they established the teacher was directly involved in the planning of the attack.
Clan militias believed to be from the Degodia clan on Tuesday morning descended on families in Dumaal village of Malkamari ward killing five women, a minor and four men.
County commissioner Onesmus Kyatha said the government was in control and has restored normalcy.
He said the government is rounding up more suspects. Nobody will be spared, he said.
"We are following up chiefs in Dumaal and government officers found to have contributed to the killings will bear their own burden," Kyatha said.
Citizens spreading hate messages on social media will also not be spared, the administrator said.
He thanked local leaders and residents for cooperating with security agents to restore peace.
Governor Ali Roba, who on Wednesday accompanied local leaders and security officers to the area, welcomed the latest development and urged the state to bring the killers to book.
"We cannot allow a few individuals to disrupt the hard-earned peace we worked so hard to get and are enjoying at the moment. Such characters should be apprehended to face the full force of the law," Roba told the Star on the phone.
He said leaders are traversing the county with peace meetings using the local radio stations to ensure Tuesday's incident does not spark inter-clan clashes.
The government has beefed up security with intensified patrols to disarm locals holding firearms illegally.
Local leadership led by Roba and the county commissioner have pitched camp in the area to defuse the fast-rising tension following the incident.
Edited by R.Wamochie
