CPR X TCASII TA WITH VFR ACFT Y. SEE AND AVOID CONCEPT.

Narrative

I WAS WORKING A COMBINED RADAR APCH/ARR POS. TFC WAS VERY LIGHT. CPR X DEPARTED HPN RWY 34 (RWY 34 SID; MAINTAIN RWY HDG; 1000 FT; L HDG; 295 DEGS; MAINTAIN 3000 FT). CPR Y CHK-IN LEAVING 1700 FT (MODE C). AT SAME TIME I OBSERVED A MODE C TARGET NW OF HPN AT 2400 FT NWBOUND. I RADAR IDENTED CPR Y; ISSUED TFC AND A R TURN; HDG 340 DEGS. CPR X DID NOT SEE ACFT Y. I CHKED WITH HPN TWR; ASKED IF CPR X AT 2400 FT WAS ON HIS FREQ AND TWR ADVISED 'YES' AND THAT TFC WAS ISSUED TO CPR X. I THEN ASKED CPR X IF IN FACT TWR HAD ISSUED THE TFC AT 2400 FT. THE PLT SAID YES AND THAT ACFT Y WAS ON TCASII BUT HE NEVER DID SEE ACFT Y. THERE WAS NO CONFLICT ALERT ON MY RADAR SYS. I DID NOT ASK CPR X IF HE RECEIVED A TCASII RA. THE SHIFT SUPVR CALLED THE HPN SUPVR. THEIR FEELING IS 'THAT ONCE TFC IS ISSUED; THEY HAVE DONE THEIR JOB' (MY WORDS). THIS HAS HAPPENED ON A NUMBER OF OCCASIONS EITHER; 2 IFR ACFT DEPART; THE SECOND BEING FASTER; OR A VFR WILL DEPART; NOT CONTACT DEP; THEN AN IFR WILL DEPART AND OVERTAKE THE VFR. HPN HAS NO PROB WITH THE OP 'ISSUE TFC; CONTACT DEP CTL.'