bigger. this is big. and that's bigger. rap star tupac shakur died last night after a brief life in a rough business. he was 25. >> shakur has been at the center of a battle between east and west coast rappers. >> for the second time in six months, a star in the often brutal world of gangsta rap has been gunned down. >> music industry sources on the west coast suspect that smalls' death may in some way be payback for the september killing of rap star tupac shakur. >> when tupac and biggie were