Kenya Forest Service wardens shot dead a herder during the eviction the Sengwer community from Embobut forest on Tuesday sparking outrage.
Locals said the security officers also critically injured another herder when they stormed the forest at Kisitona area in Kapyego ward.
This came barely a week after the EU called for dialogue to end the row over the ongoing eviction.
The European Union urged state authorities to hold talks with members of the indigenous Sengwer community.
The lot is reported to have moved back into the forest after they were evicted and compensated in 2014.
Paul Kiptuga, a Sengwer community spokesman, said the wardens shot Robert Kirotich dead and hid the body in a thicket near the forest.
Kiptuga said the wardens arrested David Kosgei who was injured in the shooting and took him Chesoi police station.
"It is shocking that the state has resorted to killing its citizens instead of protecting them," Kiptuga said.
He said locals in the area are living in fear following the death after Kirotich’s body was found on Wednesday morning.
But Stephen Chesa, KFS North Rift head of operations, said the herders shot at wardens who were patrolling the forest.
"There are people who fired at our officers who were in the forest accompanied by a local chief and area assistant deputy county commissioner."
He confirmed that one person was arrested in the incident and said the wardens were defending themselves after they were shot at.
"Our officers were doing their work inside the forest. They were in the right place and those who attacked them were the ones in the wrong place," he said.
Chesa said one person, who fractured his leg during the incident, was rushed to a local hospital by the wardens.
But Chesa’s remarks were dismissed by the community spokesman who said the locals were herding their livestock.
"Can KFS tell us who among their wardens was shot by the herders?" Kiptuga said.
He said the brutal killing goes against calls by EU to suspend hostilities and promise by security agencies that eviction in the forest will be carried out in humane manner.
Kiptuga claimed that security agencies are targeting to cow the community through violent attacks so that it can not partake in utilisation of Sh3.6 billion water towers conservation grant to be paid out by EU.
Former Kapyego MCA Benson Kiptire said killing innocent locals will not help in conservation of the forest.
Separately, human right activists raised concerns over the killings saying the frequent harassment by security agencies must stop.
Kenya National Commission on Human Rights (KNCHR), National Coalition for Human Rights Defenders, Amnesty International, and Katiba Institute condemned KFS.
KNHCR vice chair George Morara said forced evictions constitute violations of human rights, including the rights of the Sengwer to housing, and to their ancestral lands, under international law, African Union human rights standards, and the Constitution of Kenya.
"We call on the European Union to immediately suspend the Water project until government guarantees a permanent halts to these violent forced evictions, allows the Sengwer to return to the forest and the independent investigation by the KNHCR is complete," he said.