The Mexican attorney general's office hit back Monday at new criticism of its conclusion that 43 missing students were slaughtered, after foreign experts said the probe was marred by mistakes.
An Argentine-led team of forensic experts said that while they could not exclude the possibility that the students were incinerated in a landfill by a drug gang, there was "no scientific evidence" to say that for sure.
But the attorney general's office issued a statement rejecting the "little sustained arguments" of the Argentine forensic anthropology team, which was hired by parents of the 43 young men to participate in the probe.
"It is unacceptable that -- in the face of a body of evidence, expert (investigations), confessions, statements and investigative inspections -- there are attempts to sow doubts that around 40 people were executed and incinerated in that location," the statement said.
Attorney General Jesus Murillo Karam declared on January 27 that he had the "legal certainty" that the aspiring teachers were murdered in the southern state of Guerrero in September after corrupt police handed them over to the gang.
Only one of the students was identified among the charred remains.
Human rights groups have criticized Murillo Karam's conclusions, saying the investigation relied too much on witnesses in a country where authorities often get coerced confessions.
The case has sparked angry protests, engulfing President Enrique Pena Nieto in the biggest crisis of his administration.
Parents of the students have refused to believe their sons are dead, saying they do not trust the authorities.
The Argentine experts noted on Saturday that several fires had been set at the landfill since 2010, meaning physical evidence collected at the site could belong to other events unrelated to the case.
But the attorney general's office responded that all evidence links the site of the ashes to the day the students went missing, and that any "opinion to the contrary is hypothetical and far from reality."
Among other complaints, the Argentines said they were not present in late October when divers found a bag filled with charred remains that was dumped in a river at the bottom of the landfill in Cocula.
Prosecutors responded that the Argentine team had been invited to the site the night before, but decided to focus on the garbage dump instead.
Authorities admitted that they had made mistakes in 20 of the 134 genetic profiles provided by parents of the missing but that it was corrected within 24 hours.
The genetic profiles were sent to a world-renowned forensic lab at Austria's Innsbruck University, which was only able to identify one of the students among 17 sets of remains sent by Mexico.