A blast on Thursday killed a Libyan military prosecutor in the eastern city of Benghazi who was in charge of cases involving Gaddafi-era regime officials, a security source said. Yussef Ali al-Asseifar died when a bomb placed under his car exploded, the source told AFP on condition of anonymity, adding that the prosecutor\'s brother was also killed in the blast. Hospital officials confirmed the deaths. Asseifar was probing several cases involving officials from the toppled regime of long-time dictator Muammar Gaddafi. Cradle of the 2011 uprising that ousted Gaddafi, Benghazi has been rocked by a series of killings of soldiers and police who served under the former regime, as well as judges. Libya\'s new rulers have struggled to re-establish order and form a professional police force and army since Gaddafis overthrow. They face former rebel fighters who run powerful militias and refuse to be reined in.