In the Ellery Queen television series of the mid 70´s there are some common actors. Even that series was written by Levinson- Link so maybe that´s why.

Ida Lupino, Don Ameche, Mel Ferrer, Sal Mineo, Roddy McDowall and Ray Milland.
The most pesistent one was journalist Frank Flanagan ( Ken Swofford).
There was a "Frank Flanagan" even in one Columbo episode but Swofford didn´t
play that role.