Mexico's National Human Rights Commission (CNDH) is questioning the government's investigation into what happened to 43 missing college students who investigators say were killed and incinerated last September in Iguala, in the southern state of Guerrero.
The commission on Thursday issued a list of 32 omissions in the investigation and recommendations that it said are vital to solving the case, even though Mexico’s attorney general's office gave its official version of what happened in January.
Its report lists key people and evidence, including a cellphone message from one student after he was abducted, that were never pursued in the Sept. 26 attacks.
"All of the things listed are not in the case file, and so in our view have not been done. And they are things very important to the case," said commission president Luis Raúl González Perez.
The attorney general's office said only that it had received the report and did not comment on its criticisms. The agency reiterated that it is committed to an exhaustive and transparent investigation.
The teachers college students disappeared while commandeering transit buses for a protest in Mexico City.
The government of President Enrique Peña Nieto has said the students were detained by local police and handed over to a drug cartel, which killed and incinerated them at a garbage dump. Their remains were allegedly put in garbage bags and dumped in a nearby river.
But the CNDH report says that the federal investigation had not developed profiles of each of the missing students that would include basic details such as blood type, fingerprints and distinguishing characteristics such as scars or tattoos, which it termed a "basic tool" of any search.
Many of the report's observations concern the collection and analysis of evidence from the garbage dump in Cocula and the San Juan River, where bags of their remains were allegedly dumped. That part of the government's version has drawn the most criticism from families and other observers.
For example, the report lists a number of people known only by nickname who were allegedly involved at the dump, but who have not been arrested.
CNDH calls for the Navy divers who recovered remains in the river to be interviewed. It recommends comparing the soil recovered in the bags of remains with soil from the dump to see if it matches.
It says shells recovered from the dump site undergo ballistic testing to see if they match any of the recovered weapons. CNDH also suggests investigators have never established if the remains found at the river are human or animal.
The report says some soldiers stationed in Iguala with knowledge of the attacks were not questioned while others gave limited statements. Federal police also did not sufficiently detail their actions and observations that night. The report asks the Defense Department to name any missing students who were also members of the military as local media reports have claimed.
CNDH recommends that investigators identify and interview people who lived near where the attacks took place, especially those who gave refuge to some students. It says authorities never did forensic tests on clothing found near the buses where the students were initially attacked by local police.
The students’ families, the report adds, never received proper medical and psychological support and still live amid the same crime and insecurity that led to the disappearances.
The Iguala case caused national protests and outrage worldwide over the collusion between criminals and authorities that led to the disappearances.
Thursday's report seemed to support a February report by Argentine forensics experts, which found that the evidence presented by Mexican authorities did not support their claim that the students were killed and their remains incinerated.
Mexico's federal investigators have identified only one of the missing students in the charred remains that they say were found at the river. The other remains and ashes carried no identifiable DNA.
"What we're pointing out, as we've said before, is that the attorney general's investigation should not be closed and is not closed," González said.
Al Jazeera and wire services