A building on More Road, Ile-Ife, Osun State, late on Saturday night collapsed.
Ebenco Pharmacy is one of the occupants.
Sympathisers allegedly found an unidentified middle-aged man in a coma beside the debris, he was taken to Obafemi Awolowo University Teaching Hospital, Ile-Ife, where he died.
According to a source, the incident occurred about 11 pm.
He said there was a loud noise and heavy dust. The source of the noise was still unknown.
It was gathered there was a controversy over ownership of the house after the death of the owner.
Policemen were on the scene last night.
A town planner, Kunle Olagbaju, has called for investigation.
He said the manner the building caved in without a warning was an indication of a security threat.