Ukrainians are using drones and facial recognition software to investigate alleged war crimes

BUCHA, Ukraine — Searching for evidence of the killing of hundreds of people by Russian forces here, Ukrainian prosecutor Ruslan Kravchenko opened double doors leading to a boiler room south of the city. The room had been used by the occupiers as an office.

Two weeks after Russia’s withdrawal from areas around the Ukrainian capital, local and national authorities are beginning a wide-ranging investigation into alleged war crimes with the goal of building cases strong enough to persuade an international court to call the Kremlin and its soldiers into action to take responsibility.