MEXICO CITY (Reuters) - Mexico s Senate on Friday named the country s new top prosecutor for election-related crimes, after the official previously in the post was fired amid a graft scandal involving a close former aide of President Enrique Pena Nieto. Hector Marcos Diaz, a lawyer and academic with a long career in Mexico s electoral bodies, was approved as the newest prosecutor for electoral crimes with 92 senators  votes, the Senate said in a statement.    The previous incumbent, Santiago Nieto, was fired by Mexico s acting attorney general in October on the grounds that he broke a code of conduct for officials.   Nieto had given a newspaper interview in which he accused Emilio Lozoya, the former boss of state oil firm Pemex and a senior member of the president s 2012 campaign team, of writing to him to ask that he be declared innocent of funneling cash from Brazilian construction firm Odebrecht into Pena Nieto s campaign. Odebrecht is at the heart of a Brazilian bribery and kickback probe, known as Lava Jato or Car Wash, that has reverberated across Latin America. The ruling Institutional Revolutionary Party (PRI) has been trying to shake a reputation for graft that threatens to undermine the party s efforts to stay in power in next July s presidential election. The firing of Nieto was widely seen as a setback to those efforts.  The PRI has overseen the arrest of various former state governors, but Lozoya poses a more difficult challenge, given his proximity to the president. Both Pena Nieto and Lozoya have denied involvement in any wrongdoing related to the 2012 campaign. 