Three more people have died following a cholera outbreak in Kiunyu village in Gatanga, bringing the number of fatalities to five.
Murang'a Health executive Joseph Mbai said two people passed away on Tuesday and one on Thursday.
Mr Mbai said the disease was spread through drinking contaminated water from River Gathwariga.
"We have established that a truck that ferries human waste was washed in the river where local residents get water for domestic use and infected the villagers downstream.
"We will stop at nothing to arrest the culprits and charge them regardless of who they are," he said.
The truck was supplying water to Kiunyu Nyaga road, which is under construction.
Six more diagnosed with cholera in Tana River
Results of tests conducted on eight patients came out positive of Vibrio cholerae, the bacterium causing the disease.
Out of the 100 victims, 40 were admitted at Kiunyu Isolation Centre and the rest at Thika Level Five Hospital.
Families of the victims want the county to offer them financial assistance to bury their relatives.
For example, Ndung'u Mwangi, whose father died on Tuesday, said he used up his money paying bills of his four relatives admitted at Thika Level Five Hospital.