Police in Mexico have arrested a retired judge accused of tampering with evidence related to the disappearance of 43 students from Iguala more than a decade ago.

Lambertina Galeana Mar?n was the president of the Superior Tribunal of Justice in the state of Guerrero when the trainee teachers went missing in 2014.

The 79-year-old is suspected of having given an order that led to the disappearance of CCTV footage which investigators said was key to the case.

She was arrested in the city of Chilpancingo, three years after a warrant for her arrest had been issued.

The disappearance of the 43 students ? who all attended the same teacher training college in the town of Ayotzinapa ? has long haunted Mexico.

More than a decade on, and despite several investigations, much is still unknown about what happened on the night of 26 September 2014.

The remains of three of the students have been found, while the whereabouts of the 40 others remain a mystery, although they are widely presumed to have been killed.

A 2022 report by a truth commission tasked by the Mexican government with investigating the case found that it was a state-sponsored crime involving federal and state authorities.

According to the commission report, local police worked with members of a criminal group to forcibly disappear the students.

The students had gone to Iguala to commandeer buses to take them to an annual protest in Mexico City.

The Mexican government said both the police and a local criminal group known as Guerreros Unidos (United Warriors) had been alerted to the students? activities.

Guerreros Unidos suspected that the students seizing busses in Iguala had been infiltrated by members of a rival criminal gang, Los Rojos, the report alleged.

Both the police and members of Guerreros Unidos then mounted several roadblocks in and around the city, it added.

One of those roadblocks, manned by local, state and federal police was on the street outside the Palace of Justice.

Two Palace of Justice employees told investigators that the palace?s security cameras had captured what had happened at the roadblock.

However, the footage was never handed over to the authorities and when officials attempted to retrieve it almost a year later, the footage had been "lost", investigators said in 2015.

Prosecutors have since alleged that Ms Galeana gave the order to have the footage destroyed or deleted.

In an official statement, Mexico?s security ministry said Ms Galeana would face charges of forced disappearance. (BBC: Text, Excluding Headline)

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