A Kitui businessman doused himself in petrol and set his body on fire after stabbing his mother-in-law to death on Wednesday.
The man had travelled to his in-law's place to fetch his wife who had ran away from their matrimonial home following a family dispute.
Kaningo chief Samson Kitheka said the suspect was enraged that the wife was reluctant to reunite with him.
"The man arrived at his in-laws at around 10pm on Tuesday but found his wife absent."
"After spending some time with the children without their mother returning, he left a message that he would be back to punish the woman," the chief said.
He said the man returned in the dead of the night at around 1am and attempted to torch the grass-thatched house where his wife and their three children were sleeping.
"The woman woke up to a smell of petrol and was stabbed by the husband after she sought to find out where the smell was emanating from," Kitheka said.
The chief said the man also attacked his mother-in-law after she came to rescue her daughter.
"The woman died instantly after she was stabbed in the abdomen. The man fled to a nearby thicket and torched himself," the chief said.
Kitheka said the two bodies were taken to Kyuso Level 4 Hospital.
The woman and her daughter, who survived the attack, were admitted to Mwingi Level 4 Hospital.