The United Nations said Thursday there is strong evidence that Mexican investigators tortured and abused suspects arrested over the disappearance of 43 students in 2014, urging the government to punish those responsible.
There are "strong grounds to believe that torture, arbitrary detention and other human rights violations were committed" in the investigation of the still-unsolved case, the office of the UN High Commissioner for Human Rights said in a report.
Mexico is still haunted by the case of the 43 students, who disappeared in murky circumstances in the southern city of Iguala on the night of September 26, 2014.
The UN said the evident torture of suspects arrested in the case amounted to a "double injustice" -- the title of the report -- that also violated the right of the students' families to find out what happened to their loved ones.
The students had commandeered five buses to travel to a protest, but were attacked by municipal police.
According to federal prosecutors, corrupt police handed the students over to a drug cartel, which massacred them and incinerated their bodies at a garbage dump.
However, independent investigators from the Inter-American Commission on Human Rights who carried out a forensic analysis of the supposed crime scene found that version of events was impossible.
The failure to unravel the case has drawn international condemnation and been a stain on the government of President Enrique Pena Nieto.
The new report is based on a detailed analysis of the cases of 34 of the 129 suspects arrested.
It had particularly harsh criticism for federal prosecutors, who took over the investigation on October 5, 2014. All the abuses documented were committed after that date, it found.
"In all the cases analyzed... the individuals presented numerous physical injuries, certified by medical examinations, which are consistent with injuries resulting from torture," it said.
The forms of torture used included beatings, electric shocks, blindfolding, attempted asphyxiation, sexual assault and psychological torture, including threatening to rape detainees' relatives, it said.
The report urged a full probe to bring those responsible to justice, and said evidence obtained through human rights abuses should be thrown out.