Over two dozen alumni of Bernie Sanders’ (D-VT) 2016 presidential campaign wrote a letter to the Vermont senator and his team in recent weeks seeking a meeting to “discuss the issue of sexual violence and harassment on the 2016 campaign, for the purpose of planning to mitigate the issue in the upcoming presidential cycle,” Politico reports. “In recent weeks there has been an ongoing conversation on social media, in texts, and in person, about the untenable and dangerous dynamic that developed during our campaign,” the group wrote in the letter, which they reportedly sent to Sanders’ team on Sunday. The letter did not mention any specific instances of harassment—and some of the signers told Politico that it was meant to apply not only to Sanders, but also to any potential 2020 contenders.

Sanders’ campaign committee responded warmly to the letter. “We thank the signers of the letter for their willingness to engage in this incredibly important discussion,” the committee said in a statement. “We always welcome hearing the experiences and views of our former staff.” The committee noted that it had already implemented some changes to reduce the chance of harassment, including a third-party tip line and mandatory training for staffers and volunteers.