A crippled four-year-old was among eight people killed on Sunday when a residential building in Lokoja, central Nigeria, collapsed, local media reported, according to DPA. The grandmother of the child who suffered from polio was also killed in the accident, while the child's mother was reportedly in a coma in hospital. Rescue teams retrieved eight bodies from the rubble and 20 people were being treated in hospital for injuries. Reports said that the owner of the building had recently added two extra floors onto what used to be a bungalow. Although the house showed some signs of weakness when the first floor was added, the owner proceeded with adding the second floor, reports said. A local police officer, Ahmed Kareem, condemned the practice by Nigerian property developers of making adjustments to buildings without obtaining the necessary permits or employing the services of trained professionals. Police hoped to arrest the owner of the building and his building contractor, neither of whom lived in the town, Kareem added.