Though Audrey, one of the series' writers alongside Rachel Specter, didn't mention his name, the open letter did.
They wrote, "Many of us were, to varying degrees, manipulated psychologically and emotionally".
There is only ONE Tree Hill and we are all more than one showrunner; we are a supportive community of fans and cast members.
The letter, first published by Variety, goes on to say that female staffers were also "spoken to in ways that ran the spectrum from deeply upsetting, to traumatizing, to downright illegal" and some "put in positions where we felt physically unsafe".
The creation of the letter came about after Audrey Wauchope, a former writer for One Tree Hill and current writer on The CW's Crazy Ex-Girlfriend, tweeted a thread over the weekend in which she detailed the alleged inappropriate behavior she and other women experienced at the hands of an unnamed showrunner while working on the show.
'For one another. And for every male cast mate and crew member who has reached out to our group of women to offer their support these last few days. Greenberg admitted he was "shocked and saddened to hear what the women of OTH had to endure", while Nichols noted, "We have to be better".
In the series of tweets Wauchope wrote: 'I'm furious and sad and everything else for the women who have sat on that couch next to that man.
Schwahn, who acted as showrunner for One Tree Hill for all nine seasons, has not issued a statement on the allegations against him.
One Tree Hill showrunner Mark Schwahn is the latest Hollywood figure to be accused of sexual assault, adding to an unfortunately growing list of such instances.
She detailed inappropriate things he allegedly said he would do while Audrey and her writing partner, Rachel Specter, were working on the show - she said that they were told female writers were hired due to their looks, and she said in meetings the female writers would avoid sitting near the showrunner "as not to be touched".
The unsolicited advances toward female staff included putting his arm around them, petting their hair and showing naked pictures of an actress he was having an affair with, according to Wauchope's tweets. "I know he did more but not to me so they're not my stories to share", she wrote. Hahahaha we said. That's insane.
E!, the network that now hosts Schwahn's show "The Royals", also released a statement, writing, "We are monitoring the information carefully".
Collectively, the women explain that they supported and "confided in" each other during that time: "We set up safe spaces to talk about his behavior and how to handle it". A letter of support from the cast members does identify Schwahn by name. They echo the greater rallying cry that must lead us to change: Believe Women.