A former employee of the left-wing watchdog group Media Matters for America accused his ex-colleagues of covering up a sexual misconduct incident in social media posts Monday.

Timothy Johnson, formerly a senior writer at Media Matters, was threatened with a lawsuit from his former employer over a Twitter thread in which Johnson said that an editorial director at the group "covered up for a man who preyed on our colleagues."

The thread began with Johnson announcing, "After about 10 years, I no longer work at Media Matters."

In a lengthy and at times vague series of tweets, Johnson alleged that Media Matters editorial director Ben Dimiero covered up sexual misconduct by another unnamed employee who is no longer working for the group.

"I am very very fortunate in my circumstances that I did not end up on the street the next day as a consequence of what my former boss @bendimiero did. I bet a lot of people would have," Johnson wrote.

"My experience has been that the vast, vast majority of past colleagues at the @mmfa, even including most executives and managers, were wonderful, kind people to work with.

"But you two clowns? I don’t think so. Do either of you want to talk about April 4? I doubt it," he continued, referencing an unknown incident.

"Ben: Do you want to talk about how you covered up for a man who preyed on our colleagues?" Johnson wrote, addressing Dimiero.

\u201cThis man suddenly resigned. And to my shame, I went out with him after work that day and we all got really drunk. He told me a sob story, I bought it, and the night ended with him being carried up to his apartment.\u201d

— Tim Johnson (@Tim Johnson) 1654518577

He continued:

This man suddenly resigned. And to my shame, I went out with him after work that day and we all got really drunk. He told me a sob story, I bought it, and the night ended with him being carried up to his apartment.

Not too long later, I learned the truth of why he 'resigned.' He was dismissed because of his sexual misconduct. But only after years of people in authority positions knowing about what he was doing.

He apparently was still allowed to come into the office (to participate in a poker game). I ran into him on the street, just outside the office, a month or two later after I learned this. He gave me a friendly hello.

I didn’t reciprocate. I hope (I am no stranger to beating the fuck out of a predator) that I put the fear of god into him. The smirk on his face didn’t last long. I heard he didn’t come back to the office after that. I never saw him again, I hope he never did come by again.

I am ashamed that I did not share this publicly until now. It most likely makes me a clown myself. But brass tacks, I didn’t, and I’m sorry.

Later on Monday morning, Johnson posted screenshots of a letter he received from Media Matters attorney Ben Stafford informing him that he had breached a contract negotiating the end of his employment. The letter stated that Johnson was fired for cause. Media Matters demanded that he "immediately remove the Twitter thread you posted this morning about MMFA and your former manager."

\u201cUpdate: Media Matters (@mmfa) is threatening to sue me for doing this thread. Every statement within the thread is true. https://t.co/pOHdN9lcUa\u201d

— Tim Johnson (@Tim Johnson) 1654566314

Stafford wrote that Johnson had been fired for "abandoning work shifts" without proper notice and "insubordinate and bullying communications" sent to his coworkers. As part of the agreement ending Johnson's employment, he was not to "directly or indirectly, disparage MMFA, its officers, directors, or employees, or MMFA's business, and will not encourage any third parties to do so."

"You have unquestionably violated this obligation," the letter states. It called the accusation against Dimiero "false and defamatory" and said Johnson's tweets "indisputably disparage both MMFA and a current MMFA employee in clear breach of the Agreement."

The letter states that Media Matters reserves the right to sue Johnson for monetary damages if he did not delete his tweets by close of business Monday.

Johnson's thread is still on Twitter as of Tuesday. He maintains "every statement within the thread is true."

Media Matters did not respond to a request for comment.