The Post claim they have a source who has informed them that Macro recovered a DNA profile in 2011. That's 5 years ago. We know a heap of publicly named suspects and without a doubt there would be suspects we don't know about. I believe in this context "suspect" and "POI" are interchangeable.
So would it be reasonable for the source to say to BC, "Macro have DNA and LW, PW, SR etc have been ruled out, but since the other suspects are not public, I can't tell you their status"? It seems unlikely. It's more likely he said, "Macro have DNA and it doesn't match any of the suspects they have taken a DNA sample of".
My assumption is BC is saying the DNA profile doesn't match any of the suspects who they have a DNA sample of, meaning "Known" implies "known to Macro" rather than "publicly named suspects".
I find this interesting;
Unsure why he's hinting at the motivation of his source?