I don't know what to tell them. Where would I find a transcript of the show I was watching last week at PBS? I'm not ducking the request, just not sure how to proceed. All I know is I was watching PBS evening news, and Margrete Warner was interviewing the two Senators on the issues of prisoner abuse. I don't even remember which day it was.
Might check PBS if they have a log accessible concerning the material of the show. If not, I'd just narrow it to a concise catchy headline on your E-mail header..
Something like,
On PBS/Senator Kit Bond Smacked down Durbin for Nazi Slur
Give the details you have. Their choice if they want to follow up. Maybe shop it to a few blogs and hope one bites willing to do the research.