LAGOS, Nigeria — Sunday Adeyemo left his home on crowded Lagos Island early Wednesday as he always does, only to receive devastating news just hours later: The three-story building that housed not just his family’s apartment, but a primary and nursery school, had collapsed.

His 7-year-old daughter was inside. She did not survive. At least eight people have died, Nigerian officials said by late Wednesday evening.

“I’m totally devastated,” said a badly shaken Mr. Adeyemo, who was on the way to the hospital to collect the body of his daughter, Taiwo, a second-grader.

Scenes of horror and grief surrounded the building that had housed the Ohel Nursery and Primary School on Wednesday, as terrified parents and hundreds of onlookers hoped for the best. At least 70 people were inside the building at 10 a.m. when it fell, and possibly many more, neighbors said.