In Marafa village, the attackers torched four houses and beheaded a 72-year-old man.
In recent months, Lamu County has witnessed repeated attacks by suspected Al Shabaab militants.
A 72-year-old man was beheaded on Saturday evening by suspected Al-Shabaab militants in Marafa and Poromoko villages in Lamu County.
Local administrators who spoke to Nation.Africa on Sunday on condition of anonymity, said the incident happened when the heavily-armed assailants raided the two villages around 9pm. The attackers also torched atleast 10 houses.