Tomas Zeron, the director of investigations at the attorney general's office, told Enfoque Noticias radio that forensic experts and the testimony of suspects backed the government's original conclusion.
But he separately told Imagen Radio program: "We are sure that what happened was that there was a big fire. A large group of students was burned there, without being able to confirm that it was all 43, but it was a large group of students."
Attorney General Arely Gomez said on yesterday that her office would take the commission's report into account and she ordered a new forensic investigations at the dump site.
Zeron said the new forensic investigation would "attempt to reach a unanimous decision about what happened there and validate our (conclusion)."
The commission cited an international fire expert who concluded that it would take 60 hours and nearly 60 tonnes of wood, tires and diesel to cremate 43 bodies.