The head of a commission charged with searching for tens of thousands of missing people in Mexico has stepped down, as critics accuse the government of trying to undermine the true scale of the disappearances.

Karla Quintana, head of the National Search Commission, did not elaborate on the motives for her resignation, saying only that she is leaving “in light of current circumstances”.

“The challenges surrounding the disappearance of people remain,” Quintana posted Wednesday on X, the social platform formerly known as Twitter. “The State must continue to push for a comprehensive policy geared toward prevention, searching and fighting impunity.”

Escalating cartel violence has increasingly eclipsed large swathes of the country, with thousands of Mexicans reported missing this year alone.

Populist President Andres Manuel Lopez Obrador’s government has recently come under criticism for announcing it would carry out a census of the country’s disappeared. Critics say this is a tactic to manipulate numbers and “present a fictitious decrease” in those missing ahead of the 2024 presidential elections.

Hoy he presentado al Presidente mi renuncia al cargo de Comisionada Nacional de Búsqueda de Personas.

Dirigir la CNB, trabajar para mi país y para las personas desaparecidas y sus familias, construyendo un proyecto de Estado, ha sido un gran honor. pic.twitter.com/ObwaEm9JiB

— Karla Quintana O. (@kiquinta) August 24, 2023

More than 110,000 remain missing across the country, according to figures from Quintana’s commission — likely an undercount due to lack of reporting, distrust in authorities and endemic impunity. Many families of those who have disappeared have taken it upon themselves to seek justice, often with fatal consequences.

Lopez Obrador appeared to approve Wednesday’s departure; he appointed Quintana in 2019. When asked about the resignation at his Thursday morning news conference, he said it “closed a circle, and we are free”.

He added that his government continues to make progress in the search for the disappeared.

Last year, the special prosecutor leading an investigation into the notorious 2014 abduction of 43 students in southern Mexico resigned, citing disagreements with the Attorney General’s Office. International watchdogs said at the time that his unit lacked support to collect evidence and carry out judicial proceedings.

Meanwhile, human rights groups — including the Center for Human Rights Miguel Agustin Pro Juarez — expressed concerns about Quintana’s resignation, saying that moves by Lopez Obrador would “reverse advances” made in the effort to track down the missing and bring perpetrators to justice.

Quintana and her team’s work “put a previously languishing state institution on its feet”, shining a light on the “crisis of disappearances while facing resistance from prosecutors”, the centre said.

The number of disappearances exploded in 2006 when Mexican authorities declared war on the drug cartels. For years, the government looked the other way as violence increased and families of the missing were forced to become detectives.

Since then, cartels in the country have broken into factions and warred with each other for territory, only deepening the violence.

In 2018, a law was passed laying the legal foundations for the government to establish the National Search Commission. There followed local commissions in every state; protocols that separated searches from investigations; and a temporary and independent body of national and international technical experts supported by the United Nations to help clear the backlog of unidentified remains.