Their disappearance come amid mysterious deaths in their family beginning with their mother, whose mutilated body was found near Paradise Lost on Kiambu Road last week.
READ Daughter to deceased lawyer Magu found dead
Their father, lawyer Paul Magu died days later after being hit by a bus on the Thika-Garissa highway in a suspected suicide case. He had left their Nairobi home with the three children a day earlier.
Magu is thought to have committed suicide after killing his wife.
A search for the two missing boys aged nine and eight has been narrowed to a forest near Tatu City, not far from where their sister’s body was found.
READ Help us find these kids – police
Police believe the father was linked to a religious cult tracing its roots to Nigeria.