David Waweru was watching a World Cup match in a bar in the Kenyan coastal town of Mpeketoni when fighters from Somalia's Islamist al-Shabab militant movement apparently began their attack.
The first target on Sunday night was the police station, where dozens of gunmen fought a fierce battle with the outnumbered local police. The sound of gunfire alerted the rest of the town that something was wrong, but few could imagine what would happen next.
"We were watching football when the shooting started, and the owner asked us to leave," Waweru recounted, saying he left the Costa Rica cafe and, in a decision that would save his life, hid in the darkness behind a house.
Across the road was Mama Monica's Guest House, and from his hiding place the young man watched in horror as the next phase of the attack played out.
Waweru said the people inside initially hid in their rooms, only to be hunted down and hauled to the dusty street outside.
"They arrived and asked people to get out. They asked them to lie down, and then they shot them one by one, right in the head, one after another."
The al-Shabab also appeared to single out non-Muslims for immediate execution - Mpeketoni is known as being home to mainly Christian settlers from central Kenya.
"They asked people if they know anything about Islam. They wanted you to give
shahada," or recount the Muslim profession of faith, Waweru said, adding that the killings were carried out to chants of "Allahu Akbar" (God is Greatest).
"They did not kill women and children, only men. They said they were doing that because the government of Kenya is killing people in Somalia."