Independent forensic experts have rejected the Mexican government’s investigation into the 2014 disappearance of 43 student teachers, concluding that there is no physical evidence to support the attorney general’s claim that the missing students’ bodies were incinerated at a rubbish dump.

Investigators from the Argentine Forensic Anthropology Team (EAAF) combed through the dump near the town of Cocula in the state of Guerrero but found nothing to suggest a single fire was ignited the night of the students’ disappearance.

And while the remains of 19 bodies were found at the dump, there was no evidence to conclude they included the missing students, said the team’s report, released in Mexico City on Tuesday.

The findings further discredit the Mexican government’s handling of one of the most notorious crimes in Latin America’s recent history. A federal investigation concluded that the students from the Ayotzinapa training college were killed by criminals before their bodies were destroyed on a bonfire of tyres that burned for 60 hours before their ashes were thrown into the nearby San Juan river.

The attorney general at the time, Jesús Murillo Karam, described the conclusion as “the historic truth” in an attempt close the case on a crime that had provoked mass protests across the country and sent President Enrique Peña Nieto’s popularity plummeting.

But the EAAF team concluded that the scientific evidence did not support the official version. “From the scientific point of view and the evidence collected and analysed … it is not possible that the suspects could have burned 43 students in that place,” the report said.

The EAAF report was the second independent investigation to reject the government’s conclusions; last year, a team from the Inter-American Commission on Human Rights (IACHR) concluded that the official account of events was scientifically impossible.

Families of the missing teachers expressed satisfaction with the EAAF report that vindicates their rejection of the official investigation, which they said was based on interrogations and never considered plausible. Despite the lack of any supporting evidence, they continue to insist their children are still alive.

“This is proof of what we have said and what we have always known,” said Mario González, whose son, César Manuel, is among the missing. “‘The historic truth’ has fallen to pieces with this report.”

The report follows a year-long review of evidence from the garbage dump, 20km from Iguala, where the students commandeered the buses in order to travel to a protest before coming under fire from corrupt municipal police officers. Authorities allege the police, acting in cahoots with organised crime, kidnapped the students and turned them over to criminals, who killed them and burned their bodies in a garbage dump.

Investigators say they found evidence of recurring fires in the dump, but nothing to suggest a single inferno on the night the students’ bodies were supposedly burned. Those recurring fires made it difficult to determine when damage in the dump was done, while the heat generated was insufficient to reduce human remains to ashes.

Evidence from firearms such as shell casings showed signs of being tampered with, while the kind of ammunition did not match the weapons the suspects said they used.

EAAF investigators say they found an abundance of human and animal remains, in the tip, but distinguishing between the two was often impossible. At least 19 persons were determined to have been buried in the tip; none, however, were students from the Ayotzinapa normal school.

More than 100 persons have been reported missing in Iguala, with most of the cases coming to light after the abduction of the Ayotzinapa students, the investigators said.

A laboratory at the University of Innsbruck, Austria, identified a bone fragment found in the San Juan river as belonging to student Alexander Mora. The EAAF confirmed the finding, but questioned the chain of custody for the evidence containing the bone fragment.

EAAF team member Mercedes Doretti called that bone fragment, “atypical”, as it was larger than most of the remains found in the garbage tip and did not show signs of injury produced by fire.

In September 2015, the Austrian lab also identified remains likely belonging to a second student, Jhosivani Guerrero de la Cruz. EAAF investigators say the test is insufficient to conclusively determine if the remains were in fact Guerrero.

Investigators from the IACHR have also released a report calling the fire-theory into question. IACHR investigators reviewed satellite photos and weather station records in Iguala on the night of the attack on the students, and found no evidence of fires in the area. Additionally, 21.8mm precipitation fell at time the bodies were supposedly being burned.

Guerrero state, site of Iguala, has remained racked by violence since the attacks on the Ayotzinapa students, despite a change of state government three months ago.