Mexico's president on Tuesday promised an in-depth investigation to find those responsible for the deaths of at least 24 people in the collapse of an elevated metro train line with a history of problems.
The vow came as emergency services in the capital worked to retrieve the bodies of victims still trapped in the wreckage of the carriages that plunged towards the ground on Monday night.
Dozens were injured in the accident, one of the worst ever to strike the Mexico City metro, raising questions about construction and maintenance standards on a network used by millions every day.
