I think this is one of those difficult cases where some people say one is correct, other people say the other is correct. And they both have good reason.
Those who say "they" is correct would say that "they" is the complement of the verb "to be" -- but also that the complement in English is in the subjective form. If someone asks, for example, "Who is it?" they would reply "It is I."
However, many people now say that the complement of "to be" in English should be the objective form. In fact, most people do say "It's me", although some say it's not actually correct, it's slang; while others say that this is perfectly correct, and "It is I" is actually wrong. If you agree with those who say that "It is me" is correct, then you don't have to worry whether "they/them" in your sentence is the complement of "to be" or the object of "to" -- in either case, it's "them".
Confused? Well, so are a lot of native speakers and students alike.
The best solution, I think, is to find a different way to say the same thing. For example: "Were they the ones referred to on the news?"