Mexico City metro: 'My dad never came home'

Mexican authorities have promised a full investigation into the collapse of a metro overpass in Mexico City, as questions mount over the line's safety.

The elevated track on Line 12 fell on to a road, killing at least 24 people.

Concerns over possible structural failures had been raised since the line was inaugurated, in 2012.

There were concerns about design problems and construction standards, as well as allegations of corruption.