A B767-300 RECEIVED AN RA AT 12500 FT DEPARTING SKBO. THE DETECTED TFC WAS INITIALLY 1000 FT ABOVE AND CAME WITHIN 100 FT BEFORE DISAPPEARING BEHIND THE ACFT. THE TARGET WAS NEVER VISUALLY DETECTED.

Narrative

WE HAD BEEN CLRED ON THE GUY 5/ZIP TRANSITION TO 17000 FT DEPARTING OUT OF SKBO WITH NO TFC ADVISORIES FROM SKBO DEP. ON CLBOUT PASSING 12500 FT; I NOTICED TFC ON TCAS SHOWING +10 ABOVE DIRECTLY ON OUR COURSE COMING OPPOSITE DIRECTION. THE TCAS PICKED UP AN ADVISORY MOMENTS LATER THEN THE COMPUTER QUICKLY WENT FROM AMBER ADVISORY TO RED RESOLUTION COMMANDING A 'MONITOR VERT SPD;' REDUCING OUR CLB RATE TO APPROX 300 FPM CLB WHEN A SECOND LATER THE TARGET BEGAN A DSCNT INTO US AND THE TCAS BEGAN SHOUTING AT THE TOP OF ITS LUNGS; 'DSND;' WITH MASTER WARNINGS. WE WERE IN BROKEN IMC CONDITIONS SO WE STARTED A DSCNT WHILE THE TARGET FOLLOWED US DOWN INTO THE MOUNTAINOUS TERRAIN OF SKBO. I RADIOED SKBO WHAT WE WERE DOING TRYING TO FIND OUT ABOUT THE TFC. SKBO STATED THERE WAS NO TFC ON THEIR SCOPE AND WE NEVER GOT A VISUAL IN THE BROKEN CLOUDS. AFTER WE 'CLRED' THE TFC; SKBO INFORMED US THAT THE PREVIOUS ACFT DEPARTING RPTED THE SAME EVENT AND ALSO DIVED TO AVOID A COLLISION THAT RADAR ON THE GND NEVER INDICATED. IT WOULD HAVE BEEN NICE TO KNOW ABOUT THAT FROM SKBO. IS SOMEONE ABLE TO PROJECT A FALSE TCAS SIGNAL TO INTENTIONALLY CREATE CONFLICTS? WE TOLD SKBO TO LET THE FOLLOWING ACFT KNOW BUT HE STILL THOUGHT THERE WAS NO PROBLEM.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR NOTED THAT THE TCAS WAS OPERATED IN THE 40 NM RANGE AND THAT THE TARGET WAS FIRST DETECTED 40 NM AHEAD OF THEIR ACFT. FROM THAT POINT THE PROGRESSION WAS JUST 'LIKE IN THE SIMULATOR' BECAUSE VERY QUICKLY THE ACFT WENT YELLOW; RED; THEN RA COMMANDS ISSUED. THIS CREW SPEAKS SPANISH AND LISTENED TO THE PREVIOUS DEPARTING ACFT; AN MD80; RPT A SIMILAR EVENT EVEN THOUGH ATC REPEATEDLY STATED THEY HAD NO TFC IN THE AREA. THE RPTR BELIEVES THE SKBO RADAR CTLRS ARE BELIEVABLE BASED ON PREVIOUS WORK WITH THEM. AT NO TIME DURING THIS EVENT DID THE CREW SIGHT THE TARGET EVEN THOUGH THE SCATTERED TO BROKEN CLOUDS SHOULD HAVE PERMITTED IT TO BE SEEN. THE RPTR QUESTIONS WHETHER AN EXTERNALLY POSITIONED PERSON COULD ELECTRONICALLY MANIPULATE A TARGET PICKED UP BY AN ACFT. THIS TARGET EXHIBITED VERY DELIBERATE BEHAVIOR BUT RPTR WONDERS WHETHER IT REALLY EXISTED. HE DOUBTS THAT AN INTERNAL PED COULD HAVE CAUSED THE INTERFERENCE BECAUSE OF THE PREVIOUS ACFT'S RPT.