Earlier this month, CBS fired Peter Lenkov, who’d overseen a powerful fiefdom. V.F. spoke to 30 sources about what happens when a network gives somebody a difficult job, then seems to let problems pile up for years because he’s making it money.

The problems began on day two.

Not long before the 2010 reboot of Hawaii Five-0 became a hit for CBS, its showrunner, Peter Lenkov, recruited Sarah Goldfinger to join the staff. The offer, according to Goldfinger, was to be a coexecutive producer and second-in-command of the writing staff on the series about cops solving crimes in the sun and surf. Wowed by the show’s glossy pilot and intrigued by Lenkov’s sales pitch, Goldfinger, who had spent six years writing for the network’s juggernaut CSI, signed on.

On the second day in the writers room, Goldfinger says she noticed Lenkov’s mood darken, possibly in response to a query from her about a particular character’s moral makeup. She sensed that he considered the question an attack.

Goldfinger remembers him asking to speak to her in her office, where he put his feet on her desk, and told her that if she didn’t like her job or the stories that the team would be telling, she could leave. “What I had said was truly not a big deal,” Goldfinger told Vanity Fair. “But I understood in that moment that he was threatening my job.”

And she claims that was just his opening salvo. Goldfinger said that before long, Lenkov—who would ultimately run the CBS reboots of Hawaii Five-0Magnum P.I., and MacGyver—was screaming at her regularly on the phone during her 50-minute commute home. According to Goldfinger, when she arrived at her house, she’d sit in her driveway as he continued his tirade, at least until she could find a way to get him off the phone. Goldfinger has since been a showrunner herself, and she knows it’s a demanding job. But, she added, Lenkov’s calls were not “creative freak-outs or just displays of normal, occasional stress. This was inappropriate hostility and unacceptable workplace behavior. I’m pretty tough. I had been on some muscular shows. But this was abuse.”

As soon as her 13-episode contract was up, Goldfinger left. But another Lenkov employee, in an interview done shortly before the showrunner was fired this month, told V.F. that she had experienced a similar situation on MacGyver, in Atlanta. “Sometimes I have to hold the phone away from my ear because it’s so loud,” she said. “It’s just volatile rage, screaming, almost incoherent at times. There’s no way to de-escalate it.” Later in the interview, she added, “I’ve never been on a show with such extreme turnover. We can’t get people to stay. It’s a toxic environment, and it starts from the head down.”