Since the 19th century, the infamous Pinkerton spy agency has a history of union-busting and involving itself in businesses.<br />Now, Business Insider reports Amazon has turned to Pinkerton to monitor European workers' labor union organizing efforts.<br />Leaked documents from Amazon's Global Security Operations Center revealed analysts have been tracking workers' union organizing activities.<br />A report from Motherboard also disclosed that Amazon data analysts use social media to monitor social justice and environmental activist groups' activities.<br />It's the latest in a string of evidence that highlights Amazon's robust efforts to monitor and crack down on its workers unionizing.<br />Earlier this year, Amazon listed, but quickly removed, a job opening for an analyst that would monitor employee's efforts to organize.