By Lizbeth Diaz

MEXICO CITY (Reuters) – Mexican officials have begun scouring new sites for the remains of 43 student teachers including a garbage dump near where they disappeared five years ago, after re-opening a case that plunged the last government into a crisis.

The abduction and apparent massacre of the youths by corrupt police working with a violent drug gang drew international outrage and led to widespread condemnation of the administration of Mexico’s previous president, Enrique Pena Nieto.

Pressure has been growing on President Andres Manuel Lopez Obrador, Pena Nieto’s successor, to fulfill his promises uncover the truth of what really happened in a case that many Mexicans believe involved federal authorities.

A person with knowledge of the matter said one place being searched is a garbage lot in Tepecoacuilco, a few miles from the southwestern city of Iguala in Guerrero state where the student teachers were abducted on the night of Sept. 26, 2014.

A spokeswoman for the attorney general’s office confirmed new investigations were underway in Guerrero but said she could not say exactly where they were taking place.

Government officials said at a news conference on Thursday that people linked to the disappearances who had been freed from prison could be sent back.

At the conference, Lopez Obrador and members of his administration shed their usual suits for T-shirts emblazoned with the number 43 to commemorate the students.

“We are convinced that in the Ayotzinapa case, the only truth until now is that there is no truth,” said Alejandro Encinas, undersecretary for human rights. Ayotzinapa is where the students’ all-male college is located.

Officials added they had conducted nine searches since June to find traces of the trainee teachers and would call Jesus Murillo, the attorney general who oversaw the Pena Nieto-era probe into the disappearances, to make declarations next week.

PROBE ‘DISCREDITED’

Lopez Obrador took office in December pledging to re-open the case. His government has called the original probe into the crime “discredited” and vowed to go after the officials who led it.

Angela Buitrago, a consultant named by the Inter-American Commission on Human Rights who is helping to oversee the new probe, said it was vital to investigate military officials who were present in Iguala five years ago.

Lopez Obrador said in December that military officials should also be put under the spotlight, but it is not clear what questions if any, they have so far faced.

According to the Pena Nieto administration’s account, local drug gang Guerreros Unidos mistook the students for members of a rival outfit, killed them, incinerated their bodies in a nearby garbage dump and tipped their remains into a river.

However, the remains of only one of the 43 was ever definitively identified, and a group of independent experts later picked several holes in the official version of events.

The U.N. human rights office said in a report last year that it appeared Mexican authorities had tortured dozens of people during the investigation. Out of 142 suspects detained in the case, more than half have been released.

(Reporting by Lizbeth Diaz; Writing by Daina Beth Solomon and Delphine Schrank; Editing by Sandra Maler and Pravin Char)