An investigation into the most notorious human rights case in Mexico in recent years ended on Sunday with accusations of impunity and lack of cooperation by officials, as well as evidence of torture of suspects in the case.
As a result the fate of 43 missing trainee teachers who were apparently murdered in 2014 in the state of Guerrero, remains a mystery.
The experts complained that government obstruction prevented them from reaching the truth, including refusal to allow investigators to re-interview detainees accused of the crime. Prosecutors also failed to pursue leads in the case that the experts had suggested, they said.
"The delays in obtaining evidence that could be used to figure out possible lines of investigation translates into a decision (to allow) impunity," the report said.
The case of the teacher training college students from Ayotzinapa, and the efforts of their grieving families to discover the truth, has deeply embarassed the Mexican government. The handling of the case by officials has also prompted widespread suspicion of a cover up to protect the police and military.
The disappearance of the 43 students covered a wider geographical area than previously believed, suggesting collusion between local armed groups and the police, according to the detailed report.
"There was coordination between the police in order to create a perimeter" to prevent buses carrying the students from leaving the town of Iguala where they were last seen, Angela Buitrago, a member of the Interdisciplinary Group of Independent Experts (GIEI) told a press conference in Mexico City on Sunday.
Buitrago also said there was nothing to suggest that the students were infiltrated by organized crime as Mexican officials have suggested.
Mexiccan president Enrique Pena Nieto thanked the experts via his official Twitter account. He said the attorney general's office would analyze their report.
"With openness, responsibility and adherence to the law, the (attorney general's office) will keep working so that there is justice," he said.
The deputy Attorney General for human rights, Eber Betanzos, said in a statement that the government offered "full access" to the experts and had met most of the requests for information.
The experts agreed with other independent findings that there was no evidence to indicate the bodies of the students were burnt at a trash dump in the town of Cocula, contradicting the official government version which has laid the blame entirely at the hands of local municipal officials and a local crime ring.
The detailed report by the experts, found that several buses were attacked in an area spanning 50 miles along a road leading out of Iguala heavily patrolled by police from several local and state forces.
The entire modus operandi by police in the area indicated a concerted effort to prevent the buses leaving the area on the night of Sept 26 2014, according to the GIEI report.
The report also found that new information indicated the involvement of an even greater number people than previously suspected in order to block the road.
"Huitzuco police mobilized about 25 officers and six patrol cars to carry out a road block (....) for no apparent reason, during the key hours of that night" at the same time as the attacks were going on against the student teachers, known as "normalistas" and a soccer team, the "Hornets" of Chilpancingo, the report said.
GIEI experts also indicated that identification of a possible fifth bus allegedly carrying drugs, which was supposedly seized by students, "was not carried out properly."
After the attacks military personnel stationed nearby turned down calls for help by some students, saying it was outside their jurisdiction, the report added. Survivors said it was several hours before they received treatment at the General Hospital of Iguala.
Last week Univision reported that Mexico's Attorney General's Office allegedly used torture and offered millions of dollars in bribes to manipulate the investigation, according to legal documents and letters by some of those accused of involvement in the case.
The GIEI report said there was strong evidence suggesting the Mexican police tortured some key suspects in the case. Out of about 110 suspects arrested, 17 showed "signs of beatings, in some cases, dozens of bruises, cuts and scrapes," the report stated.
An analysis of medical reports found convincing evidence of abuse and torture of suspects, and the resulting testimony of detainees was not evaluated according to international standards. "The existence of new injuries in successive reports showed that medical evaluations did not serve as a guarantee to prevent new forms of abuse," the report found.
Regarding the disposal of the bodies, satellite information taken by Mexican authorities and the U.S. The National Oceanic and Atmospheric Administration (NOAA), showed only one point of fire in the entire state on Sept 27 2014, "which did not match the coordinates for Cocula."
Referring to the search for the missing students, the report stated that mulitple efforts had found no traces of them, "dead or alive."
Excessive bureaucracy in Mexico's criminal justice system also hampered the search effort, the experts said.
They had harsh criticism of misleading statements by Mexican authorities, poor official analysis of evidence, and the absence of the proper technology necessary to search for the sudents, as well as official efforts to negatively portray the victims.
"The investigation is more fragmented than when it started," one of the experts said.
The IACHR late last month denounced a "smear campaign" in Mexico against the work of the experts and the head of the commission. The Mexican government opposed the extension of the GIEI investigation, one of its members. Claudia Paz y Paz, the former Attorney General of Guatemala, told The New York Times.