Human rights defender Sinar Corzo was fatally shot in the southern Mexican town of Arriaga, authorities in Chiapas state said Friday.
"The murder of Sinar Corzo will not go unpunished, justice will be done. My most heart-felt condolences," state Gov. Rutilio Escandon said on Twitter.
The murder took place around 9.40 pm Thursday on a street in Arriaga, according to a statement from the Attorney General's Office, which said that it deployed a special task force to lead the investigation.
Mexico's independent National Commission on Human Rights (CNDH) condemned the killings and offered condolences to the victim's relatives.
The CNDH said it would send staff members to Arriaga, a town of roughly 24,500 people, to gather information, and asked authorities to implement precautionary measures to protect the relatives of the victim and members of the organization El Coloso de Piedra, to which Corzo belonged.
In 2015, the CNDH recommended action against Chiapas' then-governor, Manuel Velasco, and the Arriaga municipal government for mistreatment of Corzo and other activists during protests against the demolition of a market.
On Friday, Nathaniel Hernandez, director of the Digno Ochoa Human Rights Center and a comrade of Corzo's, blamed Velasco and politicians in Arriaga for the murder.
Corzo "had already received several death threats" from Velasco's team, Hernandez told EFE.