CAPT OF ACR LGT ACFT TOOK EVASIVE ACTION IN RESPONDING TO A TCASII RA RESULTING IN A DEV FROM ASSIGNED ALT.

Narrative

DENVER APCH HAD US ON A VECTOR TOWARDS THE ARPT. THE CTLR HAD JUST GIVEN US A CLRNC FOR A VISUAL APCH TO 28L WHEN THE TCASII GAVE AN AURAL WARNING OF 'TFC.' THE TCASII DISPLAY SHOWED TFC AT 2 O'CLOCK; 4 MI; IN YELLOW. I VISUALLY ACQUIRED TFC LEVEL WITH US AND AIMED RIGHT AT US. I TOLD THE CAPT THAT I HAD TFC IN SIGHT COMING RIGHT AT US AND LEVEL. SIMULTANEOUSLY; THE TCASII GAVE AN RA TELLING US TO DSND. THE CAPT STARTED A DSCNT AND I KEPT AN EYE ON THE TFC. THE TFC WAS AN ACR LGT ACFT AND HE PASSED ABOUT 1/2 MI BEHIND US AT WHAT I ESTIMATED WAS THE SAME ALT WE WERE AT. I IMMEDIATELY TOLD APCH CTL THAT WE HAD TAKEN EVASIVE ACTION BASED ON A TCASII RA. HE REPLIED THAT THE TFC HAD US IN SIGHT. WE WERE NEVER TOLD ABOUT THIS TFC UNTIL I MENTIONED WE HAD TAKEN EVASIVE ACTION. WE SHOULD HAVE BEEN TOLD AHEAD OF TIME. THE TFC IN QUESTION SHOULD NOT HAVE COME AS CLOSE AS IT DID TO US EVEN IF IT HAD US IN SIGHT. THE CAPT CALLED APCH CTL AFTER LNDG AND WAS TOLD ON THE TELEPHONE THAT THEY ADMITTED HAVING SCREWED UP BY NOT POINTING THE TFC TO US EARLIER.