Read the story in bahasa Indonesia
The Islamic call to prayer rang over Sidoarjo's tightly-packed homes, sweltering in the afternoon sun.
It was a typical Monday afternoon in the Indonesian city and the teenage students of the Al Khoziny Islamic Boarding School were gathering to pray.
"During the Qur'an reading before the prayer, I noticed something falling from the ceiling," 14-year-old Mohammad Fathulbari said.
"But I brushed it off, thinking maybe it wasn't concrete, just something else dropping."
More than 160 children were in the two-storey building when the unthinkable began to unfold.
"Suddenly, the ground shook — it felt like an earthquake," Mohammad recalled.
"I looked up, then I just ran toward the front of the mosque where the imam was.
"Kids were crying everywhere, I