Tupac certainly had some fairly high ranking civil servants, lawmen and politicians as enemies, or at least detractors. His parents were both considered political extremists, and the FBI kept a very thorough dossier on him, as he was considered a threat to the political establishment in the same vein as black civil rights leaders in the sixties and seventies. His death was convenient at best, a conspiracy at worst. It's not surprising that the investigation was cursory and left to go cold.