A residential building under construction in Lagos, Nigeria, suddenly collapsed on Monday, killing at least 4 people. It is reported that at least 50 people are still trapped in the rubble. The local government is investigating the cause of the collapse of the building, which is estimated to be related to the damage to the surrounding structure. The 20-storey residential building involved suddenly collapsed at about 3 in the afternoon. Some construction workers could not escape and were buried alive in the rubble. Local media reported that the owner was also in the building at the time of the incident and had a meeting with potential tenants at the scene the previous day. (Comprehensive report)