AP Photo/Claudio Cruz, File

FILE - In this April 13, file photo, people stand under the portraits of 43 disappeared teachers’ college students, by Chinese concept artist and government critic Ai Weiwei at the Contemporary Art University Museum, in Mexico City. One of the main suspects in the 2014 disappearance of the students in Mexico has been acquitted, released from custody on Saturday, Aug. 31, as justice remains elusive for one of the darkest moments of the country’s recent history.

MEXICO CITY (AP) — One of the main suspects in the 2014 disappearance of 43 teachers’ college students in southern Mexico has been acquitted, a human rights attorney said Tuesday, as justice remains elusive for one of the darkest moments of the country’s recent history.

Santiago Aguirre, director of the human rights center known as Prodh and a lawyer for victims’ relatives, said the judge absolved Gilberto López Astudillo due to “insufficient evidence” and the suspect was released from custody on Saturday with no pending charges remaining against him.

The case was marred by “sleaziness, human rights violations and irregularities in the investigation,” Aguirre said, adding that the prosecutor’s office failed to correct the deficiencies that happened under previous leadership.

López Astudillo has been identified as a purported member of the Guerreros Unidos organized crime group. Prosecutors during the government of then-President Enrique Peña Nieto alleged that he gave the order for the disappearances, mistaking them for members of a rival gang.

Authorities say the Ayotzinapa normal school students were abducted by police in Iguala, Guerrero state, and handed over to Guerreros Unidos.

What happened to them next has not been conclusively established.

According to officials during Peña Nieto’s 2012-2018 administration, the students were killed and their bodies burned in a nearby garbage dump. Independent experts, however, say there is no evidence to support the claim that their remains were incinerated. Possible links to actions or omissions by federal and other authorities remain under investigation.

Institutions from the United Nations to the Organization of American States to Mexico’s National Human Rights Commission have denounced what they call errors, inconsistencies, obstruction of justice and human rights violations in the investigation, including repeated acts of torture against people arrested in the case. López Astudillo was one of them.

The Mexican judicial system ruled in June 2018 that the investigation was not “swift, effective, independent or impartial” and ordered federal prosecutors to fix that.

“Judicially speaking, the case has collapsed,” Aguirre said Tuesday. “It is a very strong blow, very bad news for the families.”

Prosecutors under the former administration never accused anyone of forced disappearance, though multiple police officers were among those arrested, nor for homicide.

More than 120 people were detained, many of them as presumed members of Guerreros Unidos, but only about half remain in custody. Aguirre said among those freed are six people accused of ordering the disappearances.

Former Iguala Mayor José Luis Abarca and his wife, María de los Ángeles Pineda, are currently behind bars awaiting rulings on their appeals.

The court considered more than 100 elements of evidence in López Astudillo’s case, according to Aguirre. Sixty-two of them were ruled inadmissible for reasons such as they were obtained through arbitrary detention or torture, and the rest were not deemed sufficient to win a kidnapping conviction.

In January of this year, President Andrés Manuel López Obrador, who took office the previous month, installed a truth commission to clear up the disappearances, bringing hope to victims’ relatives. To date, however, no more is known about the students’ fate.

For the families, news of López Astudillo’s release was more bad news, said Felipe de la Cruz, their spokesman.

“It is regrettable that people have to go free because of negligence,” de la Cruz said.