A300 ACFT IN DSCNT WAS GIVEN VFR TFC AHEAD. RPTR CAPT SPOTTED TFC WHICH COINCIDED WITH THE CTLR'S POS AND APPARENT ACFT TYPE AND RPTED TFC. CTLR THEN CLRED RPTR ACFT TO MAINTAIN VISUAL SEPARATION AND CONTINUE DSCNT. SHORTLY THEREAFTER RPTR SAW THE ACTUAL ACFT PASS CLOSER ABEAM.

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WE WERE INBOUND TO OAK. WE WERE CLRED TO DSND TO FL180 WITH A TA OF VFR TFC AT OUR 11 O'CLOCK POS; 17000 FT; A TWIN BEECH. WE WERE TOLD TO EXPECT LOWER WHEN CLR OF THAT TFC. AFTER ABOUT 1 MIN OF LOOKING (I WAS THE PNF) I PICKED UP A VISUAL ON TFC AT OUR 10 O'CLOCK POS ABOUT 1 TO 1 1/2 MI. TFC APPEARED TO BE LEVEL WITH; TO SLIGHTLY BELOW US AND APPEARED TO BE THE SIZE OF A TWIN BEECH. AS THE TFC APCHED OUR 9 O'CLOCK POS; I CALLED 'TFC IN SIGHT.' WE WERE CLRED TO DSND TO 11000 FT REF THE TFC. I TOLD THE PF THAT THE TFC WAS NOW AFT OF THE WING LINE AND IT WAS OK TO START DOWN. DSNDING THROUGH 17500 FT; THE 'REAL' TFC PASSED DOWN OUR L SIDE. PROB AREAS: AS A FREIGHTER WE DID NOT HAVE TCASII. TFC WAS REALLY AT OUR 12 O'CLOCK POS. ONCE I PICKED UP TFC AT 10 O'CLOCK POS; I FIXATED ON IT. ENOUGH TIME HAD ELAPSED SINCE THE ORIGINAL TFC CALL THAT THE TFC SHOULD HAVE BEEN RECONFIRMED; BOTH BY ME AND THE CTLR. WHEN WE STARTED DSNDING WITH THE TFC STILL ON OUR NOSE; THE CTLR SHOULD HAVE QUESTIONED IT. THERE IS NO WAY WE WOULD HAVE STARTED A DSCNT WITH KNOWN TFC AT 12 O'CLOCK POS.