First, the scouts saw a footprint, then a suspected spy from a rival ethnic group, scuttling off into the bush.
Expecting an attack, young men grabbed their guns and mothers grabbed their children - there are few state security forces in this remote area of northern Kenya.
Left: A Turkana warrior prays to gods after a cleansing ceremony as they found footprints of Nyangatom warriors around their settlement. Right: Turkana Chief Eipa Choro raises his hand as he prays to gods.
Where I visited, families drink from the same muddy pools as their livestock. There are few schools - children instead help herd the precious cows to nearby watering holes.
Chief Eipa Choro, 74, said the community felt abandoned by the government; clean water from an aid group's borehole was two hours' drive away. The nearest police station took several hours to reach by road.
Left: A Turkana warrior uses a bow and arrow to bleed a cow. Right: A Turkana warrior bleeds a cow.
As part of their preparations, they slaughtered a bull then plunged their hands into its stomach to draw out the half-digested grass. They rubbed this over their heads and chests, part of their preparations to fight.
Mawien Makol, a spokesman for South Sudan's Foreign Ministry said the work might be finished by the end of the year.
Irene Akao Agum, a spokeswoman for Kenya's Attorney General's Office, said authorities were trying to gather information from both communities about the border.
My hosts want to stay in Kenya, but these days in the Ilemi Triangle, there is little peace.
Photo editing by Gabrielle Fonseca Johnson, Writing by Katharine Houreld, Editing by Mike Collett-White, Mark Heinrich