The gunman behind a deadly shooting at Brown University in December appeared to have been aggrieved by personal failures and sought retribution against those he deemed responsible, federal authorities said on Wednesday. More than four months after Claudio Manuel Neves Valente opened fire on the Ivy League campus, killing two students and injuring nine others, officials with the FBI’s Boston division announced they had concluded a significant portion of their investigation into the shooter. Neves Valente, a 48-year-old Portuguese national, also killed a Massachusetts Institute of Technology professor, Nuno Loureiro, in a separate shooting at his home outside Boston on 15 December, authorities said. Neves Valente was found dead from a self-inflicted gunshot wound on 18 December at a New Hampshire storage facility following a manhunt. Neves Valente confessed to the attacks in a series of videos and audio recordings made after the shootings, authorities say. He did not express remorse.…