news 'Building flaws' caused deadly Mexico metro crash A preliminary report into the deadly collapse of a metro overpass in Mexico City last month has found that it was caused by flaws in the construction. Jesús Esteva, head of the city's public works department, said deficiencies had been found in building materials and structural supports along the line. More reports will be made in the coming months about the collapse, which happened on 3 May. The incident killed 26 people and has led to protests in the Mexican capital. It has also put pressure on allies of President Andrés Manuel López Obrador, and on Mexican billionaire Carlos Slim, Latin America's richest man, whose construction firm Grupo Carso was involved in building the section of train line that collapsed.