A World Food Programme (WFP) official was killed by a crocodile while swimming in Lake Turkana at around 1am on Thursday.
According to Turkana Central Sub-county Police Commander David Mburukuwa, the crocodile singled out the woman from a group of four people swimming along the lake’s shores.
The incident occurred at Christine's Campsite, where the WFP had organised a training for the county’s public service officials.
Mr Mburukuwa said they would look into the circumstances under which the incident occurred.
Turkana County Senior Warden Josphat Erupe said the lake was calm when the five went to swim.
"Two decided to leave after swimming. [After the crocodile attacked], two others scampered for safety and cried out for help," Mr Erupe said.
KWS rangers cited the crocodile when they were called for the rescue but it moved deeper into the waters, forcing them to postpone their operations.
KWS rangers retrieved the body of the woman, who was identified as Marion Waweru, at about 9am, about 50 metres away from the shores.
Residents usually swim late in the night because of the cool, soothing breeze.
Mr Erupe said this was an isolated case in an area considered safe and where hundreds of locals and visitors go on weekends and holidays.
He said no such cases had ever been reported but noted that crocodiles were in areas including Furguson gulf, Kalokol, Nachukui and Kalimapus.
He advised tourists and residents to swim in groups as crocodile don't like violent waters.
Turkana Woman Representative Joyce Emanikor called upon the national government, through the KWS, to track the crocodile so residents don't live in fear.
While sending a condolence message to Ms Waweru's family, Ms Emanikor reiterated that it was an isolated incident.
"This case cannot be used to create fear or deter holidaymakers opting for Lake Turkana. It was an accident that we are very sorry about."
The lake is an ideal holiday destination for the region because of beaches that are unpolluted.