Protests against a Canadian-based mining company linked to a Mexican murder investigation escalated Friday as about 1,500 people took to the streets to honour a slain anti-mining activist.

The protesters marched through the town of Frontera Comalapa, about 20 kilometres from Chicomuselo where Mariano Abarca Roblero was gunned down last month.

Protesters blame his death on Calgary-based Blackfire Exploration, a company that Abarca Roblero and others have called a chronic polluter. Blackfire has said it is not connected in any way with Abarca Roblero's death and denied it has caused any environmental harm.

Organizers said Friday's protest was about more than the activist's slaying and was also meant to give a voice to other social issues.

"The reason for the march was for everything that happened to Mariano because there's a lot of insecurity, impunity, militarization and police presence," said organizer Gustavo Castro.

"This wasn't exclusively a protest against Blackfire but against the criminalization of social protest, and violence, and Mariano's case is an example of this."

The number of people at Friday's protest far exceeded the turnout at similar events against Blackfire held in front of the Canadian Embassy in Mexico City and during Gov. Gen. Michaëlle Jean's Dec. 9 visit to the region.

The protest was the latest in a series of actions meant to draw attention to Canadian companies with mining operations in Mexico. The demonstrations began days after Abarca Roblero was shot outside his home in southern Chiapas on Nov. 27.

He had been an outspoken critic of environmental practices at Blackfire's barite mine, saying the company was contaminating local resources. Mexican police arrested three people in Abarca Roblero's death, all of whom have ties to Blackfire.