ALBA Movimientos says the Indigenous broadcaster Efigenia Vasquez Astudillo has been killed during clashes between the Mobile Anti-riot Squadron, Esmad and the Kokonuko community in Purace, Cauca, Colombia.
Esmad officers reportedly sprayed the Indigenous group with gas as they attempted to evict them from territory at the center of a dispute.
The Kokonuko community says the land, which includes the tourist resort of "Aguas Tibias", is theirs.
Several other people were injured and were taken to the nearest medical centers in Popayan.
Police sources in Cauca have said they are evaluating the situation before making a statement, but there will be an investigation.
At least 101 social leaders and defenders have been killed between January and August 2017 in Colombia.
A recent report by the political platform Patriotic March and the organization Indepaz said 194 others received threats and 484 reported violations of human rights during the same timeframe.
According to the report, Cauca had the most acts of violence with 61 threats, 29 murders and five attacks, followed by Choco, Valle and Antioquia.
Another study by Negret, said one of the primary reasons for the violence is the continued operations of illegal armed right-wing paramilitary organizations which have occupied territory left behind by the former rebel group, the FARC.