When Oshawa native Stephanie Boyd set out to film an indigenous protest in the highlands of Peru, she knew she was wading into a heated battle between mining giants and local farmers.

She never would have guessed she'd be caught in military-style spy ring.

Boyd's coverage of the anti-mining protests put her in the right place to document what turned out to be a well-staffed surveillance operation, found to be watching over the activists and their allies for months.

Dubbed "The Devil Operation," it spawned Boyd's film of the same name, which makes its world premiere at Toronto's Hot Docs documentary festival later this month.

Boyd details the harrowing months in 2006 when a private security company stalked her, Father Marco Antonio Arana and many anti-mining activists.

At the time, Yanacocha -- a subsidiary of Newmont Mining Corporation -- had been trying to gain access to Mount Quilish in order to mine gold. 

The film alleges Yanacocha hired a private security company called Forza to follow the mine's most vocal opponents and wiretap their phone lines.

"Marco caught a young man video-taping him and the story began to unravel," Boyd told CP24.com in email correspondence. "I was working from Marco's office at the time and shared his shock… Each knock at the door made us jump."

Police eventually arrested a suspect who led them to the spy operation's headquarters, where documents, photos and computer hard-drives were seized.

They contained detailed accounts of the activists' movements, down to where they ate for breakfast and what time they returned home in the evenings.

The spies gave their subjects nicknames, including "Yoda," "The Goose" and "The Snob." Arana, a vocal leader in the movement to preserve indigenous farmland, was known as "The Devil" and his office referred to as "Hell."

"I feel a responsibility as a filmmaker to expose ‘The Devil Operation' and let the company -- and other corporations involved in similar practices -- know that they too are being watched," said Boyd, who went to school at the University of Toronto.

Boyd moved to Peru 15 years ago and works as a filmmaker, workshop facilitator and journalist. "The Devil Operation" is her third film focused on mining conflicts in Peru.

"Choropampa, The Price of Gold," is about a deadly chemical spill. Its follow-up, "Tambogrande: Mangos, Murder, Mining," follows a campaign waged by mango farmers to stop a mine from excavating their valley. Boyd directed the first two films with Ernesto Cabellos.

She says she was well familiar with the lengths mining companies would go to muzzle their opponents by the time she began work on "The Devil Operation." Once the spy ring was unveiled, she moved her edit suite to a location across the country in an attempt to maintain a low profile.

"We've had trouble with email hackers and just have to be aware that our phone and internet correspondence could be monitored," she said, noting she keeps Peru's Foreign Press Association informed of her whereabouts at all times.

The Peruvian government has refused to investigate the spy operation and its perpetrators have not been brought to justice, despite the physical evidence.

Boyd hopes her film will add to the public record on what she sees as an under-reported issue.

"In cases like this where the formal justice system has failed, the media can serve as a powerful force. The crime has been recorded and will not go unnoticed.

"Perhaps justice will not be served today or tomorrow, but at least the story will be told."

"The Devil Operation" screens at the Cumberland Theatre on Friday, April 30 at 9 p.m. and Monday, May 3 at 2 p.m.