A police report seen by AFP said police had received a tipoff about "ignorant citizens starving to death under the pretext of meeting Jesus after being brainwashed by a suspect, Makenzie Nthenge, a pastor of Good News International Church."
Another 11 people were rescued from a forest near the town of Malindi on Kenya's Indian Ocean coast and rushed to hospital, but there are fears of more victims, according to a police report seen by AFP.
The four dead worshippers have yet to be identified, while those taken to hospital included seven men and four women aged between 17 and 49, according to the police report.
Three are in critical condition.
Investigators were continuing to search in the Shakahola forest after reports of a mass grave where other cult followers may have been buried.
"The team were unable to identify the mass grave by virtue of vast land (area) and hostile residents in the forest," the police report said.
"It is further suspected that there are many victims in the forest land believed to belong to the suspect."
Media reports said Nthenge had been arrested and charged last month after two children were allegedly starved to death by their parents but was later freed on a bond of 100,000 Kenyan shillings (about $740).