Detectives shot and killed three suspected robbers in Karatina, Nyeri County, on Thursday.
Police records indicate that two others managed to escape.
"They were intercepted at Jambo in Karatina and when told to stop they instead shot at the officers," Nyeri County Commissioner Fredrick Shisia said.
According to police records, the robbers were gunned down by detectives from Special Crimes Prevention unit.
They were allegedly plotting to commit a robbery in Kutus, Kirinyaga County.
Mr Shisia said the officers had been tipped off.
Mathira East Director of Criminal Investigations Charles Kipchumba said suspects' area of operation was Karatina, Othaya and Kirinyaga.
"We caught up with them along the Karatina–Kerugoya road. When they spotted our vehicle they started shooting at our officers who gunned down three of them," he said.
Mr Kipchumba said a Ceska and toy pistols and a pair of handcuffs were seized.
The incident adds to eight the number of suspected robbers killed by police in the last two weeks in Nyeri.
Newly deployed County Commander Ali Nuno has declared war against illegal possession of firearms.
"Cabinet Secretary [Fred] Matiang’i gave an amnesty for those with illegal guns to return them. None have been returned so far. Now I am coming for them and I'm bold enough to declare war against these criminals," Mr Nuno said.