Here are some of the professor's comments in the interview in question (not the one linked in this article), from a year ago, at least this is what I think most likely to be construed by the university as targeting a group of students:
And what the students were able to do is examine video from that protest and identify, I think, three older students. We have a — Columbia has a program. It’s a graduate relationship with older students from other countries, including Israel. And it’s something that many of us were concerned about, because so many of those Israeli students, who then come to the Columbia campus, are coming right out of their military service. And they’ve been known to harass Palestinian and other students on our campus. And it’s something the university has not taken seriously in the past. But we’ve never seen anything like this. And the students were able to identify three of these exchange students, basically, from Israel, who had just come out of military service, who were spraying the pro-Palestinian students with this skunk water. And they were disguised in keffiyehs so that they could mix in with the students who were demanding that the university divest from companies that are supporting the occupation and the war, and were protesting and demanding a ceasefire. So we know who they were.