Court reform is now at the top of the agenda of Western donors to Ukraine. The European Union last year withheld $718 million in aid because the government failed to create a system for checking officials’ assets for signs of bribes. The International Monetary Fund had already halted disbursements as President Petro O. Poroshenko’s government, wary of losing control over the judiciary, has failed to establish an independent anti-corruption court.

Image A portrait of Ms. Nozdrovska displayed at her funeral. Credit... Sergey Dolzhenko/European Pressphoto Agency

Ms. Nozdrovska’s struggle for justice for her sister had become a symbol of the fight against Ukraine’s deeply rooted corruption, and was featured in television documentaries and articles in the local news media.

It began when her sister, Svitlana Sapatynska, was walking to work in her village, Demidov, not far from Kiev, and was struck from behind by a car driven by Dmytro Rossoshansky. He had previously been arrested on charges of car theft, robbery and driving under the influence, but had walked free every time.

Ms. Nozdrovska, who was 38, argued in her appeals that the police, aware they had detained the relative of the district chief judge, Sergei Kuprienko, delayed testing Mr. Rossoshansky for drugs or alcohol for eight hours, allowing him time to sober up.

A judge working under Mr. Rossoshansky’s uncle paid no heed to the bungled police investigation and released the young man on bail.