Mexico's first openly non-binary magistrate and prominent LGBTQ activist, Ociel Baena, was found dead at home in the central state of Aguascalientes, Mexican authorities said on Monday.

Baena, who used they/them pronouns, was celebrated across Latin America for their work to advance the rights of the LGBTQ community.

Mexico's Security Minister Rosa Icela Rodriguez said authorities are investigating the cause of death.

"We don't know yet ... if it was a homicide or if it was some kind of accident," she said during the president's regular morning press conference.

In October 2022, Baena was sworn in as a magistrate on the Aguascalientes state electoral tribunal in front of the rainbow LGBTQ flag, according to a photo they shared on X under the caption "Making history."

The Aguascalientes state prosecutor's office said in a statement that Baena's body was found along with that of another person, whom local media identified as Baena's partner.

Preliminary findings showed no evidence of a third party at the scene and that the deaths could have been a "personal matter", the statement said.

The authorities are carrying out a forensic analysis to determine the cause of death, the office said.

In Baena's honor, LGBTQ activists are planning vigils and demonstrations on Monday night in Aguascalientes, as well as Mexico City, Monterrey and other major cities.

Human rights organizations are calling for an investigation into whether Baena's death was related to their gender identity.

The former chief justice of Mexico's Supreme Court, Arturo Zaldivar, said he deeply lamented Baena's death.

"We lost a strong voice for equality and the rights of LGBTI+ people," he said in a social media post.