Police tape seals off an active crime scene.

A 23-year-old guy was detained on Tuesday in the Ruai, Nairobi County, after he killed his mother and seven-year-old brother in a peculiar event.

In their home on Tuesday morning, David Kimani used stones to hit the two in the head, killing them.

Peninah Njoki Kimani, 43, and Maina Karibu were identified as the victims.

A neighbor who came to the deceased’s screams and attempted to help was gravely injured when he was struck by a rock. She’s been admitted to the hospital with head wounds.

The suspect was apprehended near the crime scene, according to Nairobi police boss James Mugera.

He went on to say that they believe the incident was caused by domestic strife, but that the investigation is still underway.

“The man will be among others undergo medical tests before he is prosecuted with murder. We are investigating it,” he said.