Here's one: LSU Professor Nathan Kalmoe https://www.politico.com/magazine/story/2018/10/30/yes-political-rhetoric-can-incite-violence-222019/

... and another: Brookings Institute Senior Fellow Daniel Byman

https://www.brookings.edu/blog/order-from-chaos/2021/04/09/how-hateful-rhetoric-connects-to-real-world-violence/

... and another: American University Professor Susan Benesch:

https://www.washingtonpost.com/politics/2018/10/29/professor-who-defined-dangerous-speech-how-trumps-rhetoric-pittsburgh-are-linked/