Amazon has a complicated relationship with its employees and the latest reports are not likely to help the situation.

With an employee base closing in on 1.2 million, Amazon has been a source of reliable employment for many during the pandemic. At the same time, the company has often been criticized for its climate policies and for not doing enough to protect its workers from COVID.

Now employees have another reason to be angry at the company, as a report from Motherboard shows the company has used Pinkerton detectives to counter unionization efforts, as well as monitor environmental and social groups.

The documents show Amazon analysts closely monitor the labor and union-organizing activity of their workers throughout Europe, as well as environmentalist and social justice groups on Facebook and Instagram. They also indicate, and an Amazon spokesperson confirmed, that Amazon has hired Pinkerton operatives—from the notorious spy agency known for its union-busting activities—to gather intelligence on warehouse workers.

At a time when Amazon is already under scrutiny, this latest revelation is not likely to do the company any favors.