But the wind was shifting. In 2008, public-opinion research showed that most members of Vucic’s own party wanted Serbia to join the European Union. Vucic helped found a new bloc, the Serbian Progressive Party. Critics derided it as the same old party with a different look. Nonetheless, four years after its founding, Vucic’s coalition won a plurality of seats in Parliament. His party had deftly played to the middle of Serbian politics, promising prosperity, cleaner government and E.U. membership even as it catered to right-wing anger over Kosovo and other perceived wrongs. Vucic was too junior to become prime minister, but he gained control over the party. He was also given authority over all arms of the security services. He replaced the major department heads with loyalists.

Vucic soon began styling himself as a warrior against corruption. He ordered a series of splashy arrests, and the media took to calling him “Serbia’s Eliot Ness.” While some were legitimate targets, more than 100 of those arrested were officials of the Democratic Party that had just been ousted in the elections. Critics deplored the move as political score-settling. But the anti-corruption campaign was popular with the public and especially with the Progressive Party’s membership, which skewed to older and less educated Serbs. The party’s ratings shot up. People wanted something to blame, and Vucic had given it to them.

Among the criminals that Vucic proudly boasted of having put behind bars was Darko Saric, the Balkan region’s most powerful drug lord. Saric, the “King of Cocaine,” ran a global smuggling network and was indicted in absentia after a yearslong investigation that included the U.S. Drug Enforcement Administration. Vucic, who had just won the 2014 parliamentary election and was set to become the country’s new prime minister, called the arrest a triumph for Serbian law enforcement. Saric, who had returned to Serbia voluntarily and surrendered to the police, had a different perspective. The chief judge in the case told me that he asked Saric in court why he chose to give himself up. Saric, the judge recalled, replied that he felt safer in Serbia under the new Vucic-led government.

Like Vucic, Belivuk was shaped by the war in Bosnia, though he was much too young to play any role in it. One morning in the late winter of 1995, when the war was at its height, an explosion tore through the Belivuk family home in Belgrade, killing three. The forensic inspector at the scene that day was a man named Caslav Ristic, already a veteran at his job. When I met him in Belgrade, he was a retiree of 63 with a ruddy face, thinning white hair and a gruff manner. He had brought yellowing newspaper clippings about the explosion, along with his own Polaroid photos from the crime scene.

Belivuk’s father, Ristic told me, was a veteran who brought weapons home from the war; he was keeping two grenades in a kitchen drawer. He had been depressed, and after arguing with his wife, he walked off and triggered both grenades, apparently intending only to kill himself. His wife and mother-in-law were collateral damage. Afterward, the 9-year-old Belivuk “had to go through the hallway, past the dead bodies, to the neighbor’s house,” Ristic said. (The only visible injuries he had were some cuts.) Ristic told me it was an unusual case, but only because the father had killed himself with two grenades. “Usually they just used one,” he said.