Mexico City prosecutors have said they will bring criminal charges over construction and design defects that caused an elevated subway line to collapse in May, killing 26 people.
Ernestina Godoy, the city attorney general, said studies found that construction defects like poor welds and missing connection studs caused the collapse. She said bad design also played a role.
Ms Godoy did not identify individuals who will face charges of homicide, causing injury and damages.
But in the case of the companies involved, Ms Godoy said the goal of the criminal charges will aimed at making them pay for or repair damage both to the subway and the victims.
Criminal charges against individuals could result in prison sentences.
The results of the prosecutors’ report are similar to the conclusions presented by the private Norwegian certification firm DNV in September.
Both reports cited poorly-welded, badly-located and completely missing studs that were intended to join steel support beams to a concrete layer supporting the track bed.
But the prosecutors also cited bad welds in steel beams underlying the concrete track bed that either failed to adhere or split.
Steel struts intended to stiffen the metal beams were too short or not properly attached, and the elevated line was not designed with enough of a safety margin.
The defects distorted the train line’s framework, leading to “fatigue cracks” that reduced the structure’s ability to bear weight.
The 1.3 billion-dollar (£949 million) Line 12 of Mexico City’s metro system was built between 2010 and 2012 when current foreign affairs secretary Marcelo Ebrard was the capital’s mayor.
Mr Ebrard is seen as one of the likely contenders to succeed president Andres Manuel Lopez Obrador.
The project was plagued by cost overruns and alleged design flaws, as well as suspected corruption and conflicts of interest.
The city was forced to close the line in 2014, just 17 months after it was inaugurated, so tracks could be replaced or repaired. The section that collapsed has remained closed since May.
Some companies involved in the original construction have since argued that heavier ballast and other changes and repairs over the years may have added too much weight to the elevated line, or that it might have been weakened by Mexico City’s frequent earthquakes.