What did you do about it at the time?

Not a reasonable question. All my information was third hand at best.

We didn't play Bambaataa, R Kelly or Tupac (convicted rapist) records. That's about all a radio station could do. Can't state what legally speaking were merely rumors on the air without facing problems. All you can do is not support them commercially, which we did.

A friend of mine has worked in TV and film for decades. Many times he has told me about rumoured offenders (typically after they are arrested), but other than avoiding working on productions with them what are his choices? Trying to do a completely ridiculous "citizen's arrest"?

The same thing you did. What sort of question is that?