A fisherman was on Saturday killed by a hippo while preparing his nets for a fishing expedition in Lake Naivasha.
The middle-aged man was crushed to death at Kasarani beach as his colleagues watched in horror.
Two others were seriously injured in a separate attack at Oserian.
The attack came barely a week after environmental experts expressed concern over the closure of wildlife corridors around the lake.
They said this has led to an increase in cases of human-wildlife conflict.
David Kilo, chairman Lake Naivasha boat owners association, said the attacks have been rampant in the last couple of weeks.
He blamed the incidents on encroachment into the animal's grazing areas.
"Those injured were admitted to Naivasha sub-county hospital where they are undergoing treatment," he said.
Kilo warned that the attacks are likely to continue in the wake of the encroachment of riparian land by farmers, pastoralists, and fishermen.
"We have witnessed cases of farmers fencing riparian land locking the animals in the water. The animals attack people as they have to seek new routes."