ACR FOLLOWS TCASII RA ON SHORT FINAL WITHIN CLASS C AIRSPACE.

Narrative

EVERYTHING WAS NORMAL UNTIL TURNING (VISUALLY) ONTO FINAL FOR RWY 9L AT FLL. WE HAD THE ILS'S TUNED IN AND TFC IN FRONT OF US IN SIGHT. FROM HERE; THINGS ARE CONFUSED. WE SAW A TARGET ON TCASII OFF TO OUR R AND WE BELIEVE (CAPT AND FO) ABOUT THIS TIME ATC MENTIONED A 'BEECH DUCHESS' OFF OUR R AND A POSSIBLE ACFT CIRCLING OR THAT THE BEECH DUCHESS WAS CIRCLING. WE HAD ONLY 1 TARGET ON TCASII THROUGHOUT THIS ENTIRE MANEUVER/SIT (1 TARGET; THAT IS; IN THE AREA IN QUESTION). WE RECEIVED A TA AND SINCE THE CAPT CLRLY SAW TFC LOW AND TO THE R SLIGHTLY EARLIER; THIS TA WAS NOT ENTIRELY UNEXPECTED. THE TCASII SCREEN THEN SHOWED THE TFC BEHIND US A BIT AND THEREFORE NO RA WAS EXPECTED. ABOUT 20 SECONDS LATER (ESTIMATED) WE GOT AN RA WITH THE TCASII SCREEN SHOWING WHAT WE BELIEVE TO BE THE SAME TARGET 100 FT BELOW US AND TO OUR R -- HORIZ SEPARATION WAS UNKNOWN BUT FAIRLY CLOSE. DUE TO THE AMBIGUITY OF THE SIT; THE CAPT (WHO WAS FLYING) WAS BEGINNING TO EXECUTE (FOLLOWED RA) A GAR WHEN IT BECAME EVIDENT THAT AN ACFT DEPARTING RWY 9L WOULD BECOME A POTENTIAL CONFLICT. THEREFORE; BECAUSE WE WRE STILL IN THE LNDG CONFIGN; IT WAS DECIDED TO LAND. WE WERE NOW CLRLY IN A SAFE CONFIGN AND SIT TO LAND ALTHOUGH WE WERE VREF +20 KTS. A NORMAL LNDG ENSUED.