The circumstances of Father Juan Heraldo Viroche's death remain uncertain.

Investigators in the province of Tucuman, 750 miles northwest of Buenos Aires, told local media there were no signs of violence or "something that would suppose there was some kind of altercation with someone," the newspaper Clarin reported.

But Father Viroche, 47, pastor of the Our Lady of the Valley Parish in a locality known as La Florida, had a history on speaking out on security issues and the dangers of drug dealing. Father Viroche even celebrated a Mass outdoors in an area notorious for narcotics trafficking known as Delfin Gallo to denounce insecurity and illegal activities, Argentine media reported.

In his final Facebook post Sept. 9, he recalled warning the parish community there of "difficult times to come" and leading a march to express displeasure with the stealing of the "crown" from an image of Mary inside the local chapel.

"Far from being a robbery, it was disguised warning, the police and members of the parish community told me," Father Viroche said.

The priest's death was national news in Argentina. Concerns of potentially increasing narcotics trafficking and the accompanying lawlessness in the country so concerned Pope Francis – previously the archbishop of Buenos Aires and president of the Argentine bishops' conference – that he told a friend in a leaked letter, "Hopefully we're in time to avoid the Mexicanization."

In a statement, the Argentine bishops' conference expressed its "consternation" with the death of Father Viroche and called for the crimes to be properly investigated.

"He was known for being against narcotics trafficking. He spoke clearly inside and outside his community of defending lives that were in danger," the bishops' ministry for treating drug additions said.

"He expressed to his closest collaborators the deep pain of the threats he received from narcotics-trafficking mafias," the ministry added.