The fatal collapse happened after heavy rains in the early hours of Tuesday in the south-eastern district of Lekki, which is home to some of the most expensive real estate in the city. Leki, Lagos, Nigeria Lekki, made up of sprawling estates of gated communities with US-style suburban homes, has developed rapidly in recent years into a preferred location for wealthier Nigerians and expatriates. Some detached houses can sell for millions of dollars. Building collapses happen frequently in densely populated areas of Lagos, which is home to 20 million people. Poor workmanship and materials, and a lack of official oversight, are often blamed. But collapses are rarer in wealthier districts. The Lagos state government said in a statement that preliminary reports indicated work on the building was illegal. “The collapsed building was served contravention notice for exceeding the approved floors” and had been sealed by the Lagos building authorities before it collapsed, the government said. But the owners of the building and promoters of the Lekki Gardens development, Lekki Worldwide Estate Limited, “criminally unsealed the property and continued building beyond the approved floors”. Lekki Gardens confirmed in a statement that construction had stopped in January “over reported structural defects” but made no mention of work having resumed. It added: “Investigation is already under way to ascertain the identities of those affected as it is not company policy for site workers to take shelter in uncompleted buildings.” The addition of floors without proper planning approval was ruled to have been a factor in the collapse of a church guesthouse in Lagos in September 2014.