ACR MLG FOLLOWED WRONG ACFT ON VISUAL APCH FORCING ANOTHER ACR TO GO AROUND TO AVOID COLLISION.

Narrative

WHILE DSNDING BELOW 10000' FROM A POINT SE OF ORF; WE WERE CLRED FOR A VISUAL APCH TO FOLLOW AN LTT ON A 10 MI FINAL; STRAIGHT IN. IT IS IMPOSSIBLE FOR ME TO EXACTLY RECOLLECT EVENTS HERE; BUT AS WE PASSED ABEAM THE T/D POINT; I OBSERVED TFC ON A 1 MI FINAL; WHICH I BELIEVED TO BE THE LTT. MY COPLT ATTEMPTED TO CONTACT APCH CTL 2 OR 3 TIMES UNSUCCESSFULLY AND SWITCHED TO TWR FREQ. DURING THE LEFT TURN TO FINAL I COULD NOT SEE TO THE RIGHT AND IT BECAME NECESSARY FOR THE TWR TO PULL THE ACTUAL LTT OFF THE FINAL TO AVOID A POSSIBLE COLLISION. I NEVER DID OBSERVE THE ACTUAL LTT AND CANNOT SAY HOW FAR APART WE WERE AT THE TIME. I DO NOT BELIEVE WE WERE EVER INFORMED OF THE TFC THAT I THOUGHT WAS THE LTT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR HAS BEEN INFORMED THAT ENFORCEMENT ACTION FOR A PLTDEV IS IN PROCESS. RPTR WAS ASKED TO RELATE THE EXACT WORDING USED BY THE CTLR WHEN HE WAS CLRED FOR VISUAL APCH TO FOLLOW THE LTT. RPTR COULD NOT REMEMBER AND WOULD NOT HAZARD A GUESS. ANALYST FEELS THAT WHEN CTLR CLRED RPTR FOR THE VISUAL APCH; HE SHOULD HAVE FIRST RECEIVED AN IN SIGHT RPT FROM RPTR ON THE PROPER LTT BEFORE HE GAVE THE CLRNC FOR VISUAL APCH. CERTAINLY; THE CTLR CANNOT TELL A PLT TO FOLLOW ANOTHER ACFT ON A VISUAL APCH UNLESS THE PLT HAS RPTED SIGHTING THE OTHER ACFT. SINCE ENFORCEMENT ACTION IS IN PROCESS; ANALYST FEELS THAT CLRNC MUST HAVE BEEN GIVEN PROPERLY AND RPTR APPARENTLY RPTED SIGHTING THE WRONG LTT.