OTTAWA -- The federal government is pledging its full co-operation with a possible investigation into the role of Canadian diplomats and a former Calgary mining company in the shooting death of a Mexican activist.

Family and supporters of slain activist Mariano Abarca this week asked the Public Service Integrity Commissioner to investigate his death, filing a notice that accuses Canadian diplomats of turning a blind eye to the human rights violations that ultimately cost him his life.

Abarca, a father of four who was gunned down in November 2009, opposed a Calgary mining project in his country, saying it harmed the environment and was bad for his community in the Mexican state of Chiapas.

The complaint alleges Canadian diplomats in Mexico City were more interested in helping the now defunct Blackfire Exploration overcome local protests than upholding the values of human rights and good corporate behaviour.

Mexico's environment ministry shut the project down two weeks after the Abarca's death, citing several factors including pollution and the spread of toxic emissions.

A spokesman for International Trade Minister Francois-Philippe Champagne says the government will co-operate fully with any possible investigation by integrity commissioner, and is committed to supporting the work of human rights defenders.