Attacked, left without livelihoods and forced to flee their ancestral homes, locals in affected communities armed themselves in bids to defend their communities against the bandits.
Police reports show that more than 200 people have been killed and thousands of livestock stolen in the Kerio Valley belt alone during deadly raids since July 2021.
"The Ngoroko was initially a group of cattle rustlers who never harmed innocent children and women. But they started receiving funding and arms from powerful individuals and they became more brutal and emboldened to kill, maim and steal livestock for sale in markets outside the region," an elder Kiptoo Cheboi (not his real name) says.
The audacious bandits defied President William Ruto's order (six days ago) to surrender their illegal firearms within three days. Authorities had reportedly recovered only three firearms at the lapse of the amnesty period.
The military started hunting down the group amidst uproar by community leaders but received backing from a section of regional politicians.
About a decade ago, the bandits (Ngoroko) shot dead 40 police officers in Baragoi, Samburu County, in a show of superior military attack.
Government reports show details of a well-networked militia that sends chills down the spines of police officers and blackmails political figures into singing their tunes in return for re-election.
According to Trans Nzoia Governor George Natembeya, a former Rift Valley Regional Commissioner, dealing with the trigger-happy militia might not be a walk in the park.
"It is bigger than terrorism. Dealing with these trigger-happy bandits will not be a walk in the park. They have mastered their territory," Natembeya recently warned Kenya Defence Forces and police officers during an interview with Citizen TV, ahead of the joint operation which started on Friday.
He added: "Let them go to the field knowing that they would be dealing with battle-hardened fellows. By the way, if a bandit kills a police sergeant when he goes home, he is promoted to the same rank (within the militia)... He will be at home, waiting for the loot (from junior raiders)."
Previous government reports prepared as early as 2016 have indicated that years of environmental degradation have resulted in an acute shortage of water and pasture, fueling deadly fights for scarce resources.
The Kenya National Commission on Human Rights (KNCHR) says a 2016 report titled 'Mending the Rift,' and which was submitted to Parliament and the Ministry of Interior for action in 2017, but has gathered dust to date, would be the solution to the incessant fights.
The damning 258-page report detailed how some top security officials and politicians aided banditry and bandits between 2005 and 2016 along the Kerio Valley belt - covering parts of Baringo, Elgeyo Marakwet, West Pokot and Turkana counties.
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At least 1,400 respondents comprising locals, elected leaders and security officials were interviewed during the inquiry.
Views documented in the report implicated some politicians and senior security officials for abetting crimes in the 'Valley of Death.'
Two days ago, the commission said its unimplemented recommendations could have ended the cycle of banditry in the North Rift region, where Kerio Valley is located.
KNCHR's North Rift coordinator Kibet Kurgat says the report was shared with the ministries of Interior and Education as well as Parliament for action but had not been acted on to date.
Kurgat, who was key in the documentation of views, said an advisory has now been prepared to pressure Parliament to act on the 2016 recommendations.
"We are intending to take the advisory to Parliament so that they look into the recommendations we made. We hope that the advisory will be discussed in the House. At the moment, we have been working with government officials to look into the violence.
"We have been promised by the county and regional commissioners that action is being taken. We had also requested that they use the National Police Reservists (NPR) who have been working with the police and if they increase the number of reservists, that can help in areas that are difficult for security apparatus) to reach," said Kurgat.
He said the report had recommended adequate security in all schools located in banditry hotspots, to protect learners and teachers. He said this would have helped tame the runaway insecurity.
In its overall recommendations (in 2016), the commission gave the Inspector General of Police and the Chief of General Staff three months to apologise to families affected by the rampant banditry attacks in the entire Kerio Valley belt.
"State officials need to take responsibility for human rights violations by making a public apology to all those who are affected," the report said in part.
It also recommended a comprehensive disarmament or registration of illegal firearms in the hands of civilians as well as adequate police deployment along borders of the affected counties.
In the report are claims by residents of Baringo that senior government officials in the larger Rift Valley region abetted cattle theft by not taking any action.
In Turkana, for example, the commission recommended that the police investigate claims by locals that Turkana youth in Loima obtain guns and bullets from soldiers of a neighbouring country, who are paid in kind with rustled livestock.
KNCHR also found that police in Turkana South provided rustlers with bullets but reported that they had been given out to police reservists. In return, the commission says, the police were paid after the sale of livestock stolen in deadly raids.
The inquiry was told how a sitting MP from the county helped in planning a raid on a neighbouring community, by transporting raiders from Loima to Nadome, where 54 of the raiders were killed in the clash with herders.
In West Pokot, KNCHR noted a suspicious scheme in which police officers manning a roadblock in Kitale-Lodwar road demand bribes from motorists, but motorists who refuse to give the kickbacks are attacked kilometres away after the roadblock.
In Elgeyo Marakwet, the commission recommended that the county and the neighbouring Baringo establish why a Pokot-Marakwet peace deal that was sustained for 14 years was suddenly lost in April - June 2016.