Human rights activists are calling on a Vancouver-based mining company to pull out of Mexico after the murder of a prominent opponent of the industry last week.

Bernardo Vasquez, 32, was shot to death in his car in Oaxaca province on March 15, and two others were injured in the gunfire. He was the leader of a group opposed to a $55-million silver and gold mine operated by Fortuna Silver in the small town of San Jose del Progreso.

Supporters believe the shooting death is linked to Vasquez's activism and they told CTV News he received threats in the weeks before his death through videos posted online and graffiti sprayed throughout town.

Now activists around the world are calling for a full investigation into the recent violence.

"We don't have any proof of who was the physical responsible person of Bernardo's assassination, but there are several videos and photographs from different events that occurred in San Jose in the past months that lead us to believe that it was an act of repression coming from the local authorities acting on behalf of the Canadian company," Mexican environmentalist Octavio Rosas Landa said.

Vasquez and his group were concerned about the environmental risks associated with the mine and accused the company of not properly consulting with the community. Violence erupted in the area in January as well, when another anti-mining advocate was gunned down.

A journalist working in Mexico told CTV News that Vasquez was about to hand over photographs to the Canadian Embassy of armed mining supporters. Vasquez told reporters he believed the pro-mining camp was being funded by the company, a claim Fortuna Silver flatly denies.

Company president Jorge Ganoza Durant told CTV News that Fortuna Silver was not linked to Vasquez's murder in any way.

"It still needs to be clarified who's responsible. We're willing to cooperate in any role we're asked by the authorities," Durant said in a phone interview from Lima, Peru.

He added that violence in the community can't be blamed on the mine.

"There is a long historic struggle in Oaxaca that is sometimes difficult to comprehend," he said.

Despite calls from activists to Fortuna Silver to pull out of San Jose, the company is planning to ramp up production at the mine.

With a report from CTV British Columbia's Mi-Jung Lee