A key suspect in the kidnapping of 43 students who disappeared in Mexico in 2014 has been freed, lawyers said Tuesday, in what the victims’ families said showed the “failure” of the investigation. Prosecutors had accused Gildardo “El Gil” Lopez of being one of the main perpetrators behind the kidnapping and suspected massacre of the teacher trainees. But a judge dismissed the final remaining charge against him Monday and ordered Lopez freed, said the Centro Prodh, a rights group providing legal counsel to victims’ families. Mexico remains haunted by the disappearance of the 43 young men from the Ayotzinapa teachers’ college in the southern state of Guerrero, who were detained by corrupt police the night of September 26, 2014, and allegedly handed over to gang members who massacred them. The investigation has been marred by allegations of official incompetence or even corruption. More than 40 suspects have now been freed because of procedural mistakes by investigators, especially the use of torture to extract confessions. Lopez, however, is the highest-profile suspect released to date. Investigators had labelled him the local leader of the drug cartel that was supposedly behind the disappearance, Guerreros Unidos. “This is the first time a court has ruled to absolve a suspect in the case, which confirms the investigation has been a judicial failure,” the victims’ families and a group of organizations helping them said in a statement. “It is a consequence of the irregularities and grave human rights violations committed by the federal prosecutor’s office under the administration” of former president Enrique Pena Nieto, they said. The case was a stain on the Pena Nieto government (2012-2018). Mexico’s new president, Andres Manuel Lopez Obrador, has opened a new investigation, vowing to shed light on the crime. But the victims’ families called on the leftist leader to act “more quickly and firmly” to bring those responsible to justice. According to the prosecution’s case, corrupt police who were on the payroll of Guerreros Unidos mistook the students for members of a rival cartel. They allegedly handed them over to cartel hitmen, who slaughtered them and burned their bodies at a garbage dump. However, independent investigators from the Inter-American Commission on Human Rights found that version of events was impossible. The Pena Nieto government decided not to renew the experts’ mandate, and they never concluded their investigation. However, they hypothesized that the students may have inadvertently hijacked a bus loaded with heroin bound for the United States.