Explainer-How are war crimes in Ukraine being investigated?

FILE PHOTO: SENSITIVE MATERIAL. THIS IMAGE MAY OFFEND OR DISTURB The hand of Iryna Filkina, a woman who according to residents was killed by Russian army soldiers, is pictured as her body lies on the street, amid Russia's invasion of Ukraine, in Bucha, Kyiv region, Ukraine April 2, 2022. REUTERS/Zohra Bensemra/File Photo

THE HAGUE (Reuters) - More than 70,000 alleged war crimes have been reported in Ukraine since Russia invaded, but bringing them to trial is no simple task.

Ukrainian and Western authorities say there is evidence of murders and executions, shelling of civilian infrastructure, forced deportations, child abductions, torture, sexual violence and illegal detention.