At least 15 houses in Lugari Sub-county were gutted by a mob on Tuesday.
Residents said the attackers were avenging an alleged killing of a man by a neighbour he was in a land dispute with.
Reuben Sasaka is said to have fallen ill and died last month.
The attackers targeted houses belonging to Ababiya clan members in Chenjeni, Kulumbeni and Mutonyi villages.
There had been tension since the man's burial two weeks ago. Mcklyine Naomi from Mutonyi said she was in church when she was informed that her two-bedroom house was on fire.
"By the time I got home, my house and everything in it had been consumed," she said.
Peter Viketi, whose house was burnt, said they were wrongly accused of practicing witchcraft.
Matete Deputy County Commissioner Scholastica Kosgei said police were investigating the matter. He said five suspects had been arrested.
The attack affected learning at Mutonyi Primary School, with reports that over 200 pupils from affected villages did not report on Tuesday.
Headteacher John Soita said they may have fled.