The Israeli Mossad was not able to track these individuals as they went back into hiding in Iran. However, the institution did not forget or give up. Not that there is a direct connection but the following events happend yesterday:
A small bomb strapped to a suicide bomber exploded in the entrance to the Iranian embassy in a southern neighborhood of Beirut in Lebanon.
Right after the suicide bomber detonates his bomb, a second bomber in a much larger car bomb, drives through the Iranian embassy gates and detonates the car next to the building, killing 23 people. Among the dead, most notably is sheik Ibrahim El Ansar. The latter is the Iranian "culture" embassador to Lebanon and suspected to be the liason that funded the attack in Burgas.
It seems that the Iranians got a little bit of taste of their own medicine...