Koch Industries: use of threats to silence opposition like organized crime; use of private detectives; counter surveillance of FBI agents

The Senate investigation was marked by what was becoming a familiar pattern: those challenging the Kochs began to feel that someone was trying to watch and possibly intimidate them. Richard "Jim" Elroy, who later became a private eye himself, was at the time an FBI agent detailed to the Senate investigation [of the Indian reservation oil scandal]. His specialty had been investigating corruption in Oklahoma, and he had handled a number of tough cases, including some involving organized crime. But he soon faced a situation that he said he had never before encountered even when investigating the Mafia: he became certain that he was being followed. 

One day, Elroy stopped his car, jumped out, and confronted the driver who had been tailing him, dragging him out of his car at gunpoint, flashing his FBI identification, and warning him, "Tell your boss the next time he tries this, you'll be in a body bag." Elroy recounted that the driver explained, "I'm a private investigator who works with Koch Industries." The company's legal affairs head reportedly  denied hiring private investigators to spy on Elroy. 
...
The committee's chief counsel, Kenneth Ballen, who had previously worked as a prosecutor against organized crime in New Jersey, believed that one of his assistants was paid to get dirt on him. Luckily, Ballen said, there wasn't any. "It wasn't like politics; it was like investigating organized crime," Ballen recalled. Charles Koch, he maintains, "is a scary guy to take on. Most people back off, rather than tangling with them," Ballen observed. "These people have amassed an amazing amount of unaccountable power." (159-160)