Thiel Detective Service Company Thiel Detective Service Company The Thiel Detective Service Company was a private detective agency formed by George H. Thiel, a former Civil War spy and Pinkerton employee. The Thiel Detective Service Company headquarters were in St. Louis, Missouri. The company was formed to be a direct competitor to the Pinkerton Detective Agency, but never achieved this status. The Burns Detective Agency was Pinkerton's largest competitor. The Thiel Agency was involved in infiltrating and breaking a number of labor union strikes in the United States and Canada, much as the Pinkerton agency was. After the Homestead Strike, the Thiel Detective Agency,
Baldwin–Felts Detective Agency Agency. By then, strikebreaking work had declined. State and federal legislation outlawing the use of private detectives for the purpose of spying on or harassing workers, along with shifting public opinion, had made such detectives less useful to management in labor disputes. After the agency closed its doors, most of the company's files were destroyed or lost. The largest collection of extant files is housed at the Eastern Regional Coal Archives, in Bluefield, West Virginia. Baldwin–Felts Detective Agency The Baldwin–Felts Detective Agency was a private detective agency in the United States from the early 1890's to 1937. Today, it is