A UN expert panel condemned the murder of Mexican human rights activist on Wednesday and called for a thorough, impartial, and transparent investigation by Mexican state authorities.

Sael Silva Cisneros was a prominent lawyer, Afro-Mexican activist, and LGBTQ rights defender who was killed in an attack outside the Mexican town of Cuajinicuilapa on June 5, shortly after delivering a seminar titled: “Afro-Mexican dissidences in Guerrero: history, justice and rights.” Cisneros has a history of advocating for Afro-Mexican rights and highlighting the systemic, intersectional marginalization within Mexico and abroad. The town of Cuajinicuilapa is located close to south-western coast of Mexico and is known for having a large population of Afro-Mexicans as well as significant economic marginalization, which reflects much of the work of Cisneros.

Cisneros had also worked as a researcher for the Supreme Court of Mexico, which released a statement following his murder highlighting his work and condemning “any form of violence that attempts against the dignity, equality, and human rights of individuals.”

The UN experts reiterated Mexico’s commitments under international human rights treaties to protect marginalized groups, especially those facing intersectional and overlapping forms of discrimination, as well as to dismantle the systemic forces which uphold and facilitate these abuses. They also urge Mexico to provide “truth, justice, full reparation and guarantees of non-repetition” for said abuses.

Currently, Mexico has one of the highest rates of attack on human rights defenders and has been previously called out by the UN for its failure to protect activists despite the enactment of the Law for the Protection of Human Rights Defenders and Journalists in 2012.