I was told that Rav Amnon Yitzchak quoted the Chazon Ish saying that men in kollel who are not learning properly (or something to that effect) are considered rodfim.
Can anyone source this Chazon Ish?
You're probably looking for this quote (or one of the variations on it that are floating around):
״כל מי שמנצל לרעה את זכות הדחייה של תלמידי הישיבות, הרי הוא בבחינת רודף, וחוטא כלפי בני הישיבות״
Anyone who wrongly exploits the 'yeshiva student' [draft] deferral is considered like a rodef, and sins against the [actual] bnei yeshivot.
The internet in several places attributes this line to the Chazon Ish "as quoted by the menahel Vaad haYeshivot, Rabbi M. Tenenbaum." (Sometimes adding: in the newspaper Erev Shabbat 11.12.87. This formulation is found in the קונטרס תורתו-אמנותו of Shlomo Benizri, and others claim to have heard it from R' Tenenbaum directly, but those 'others' are semi-anonymous internet people. I also have not actually seen the newspaper that is being cited.) The quote from the Chazon Ish is also supposedly quoted in Pe’er Hador, vol. 4, p. 260; if anyone has access to this book, it would be great if you could confirm this.
(I've seen R' Tenenbaum described as a talmid of the Chazon Ish, but again, not anywhere particularly reliable.)