According to officials on Tuesday, Ukraine has been collaborating with the FBI and American firms to gather evidence of Russian war crimes, including geolocation and cellphone data.

Digital information is being collected from Ukrainian towns and battlefields devastated by the conflict since Russia’s invasion in February, stated Alex Kobzanets, an FBI special agent with prior experience as a legal attache in Ukraine. Kobzanets addressed the RSA cybersecurity conference in San Francisco, highlighting the FBI’s expertise in data collection and analysis.

The investigation involves examining cellphone data, conducting forensic analyses of DNA samples, and analyzing body parts found on battlefields. Kobzanets added that the next step involves working with US national service providers to obtain subscriber and geolocation information when possible.

Kobzanets also mentioned that the FBI has been assisting Ukraine for the past 18 months in identifying Russian collaborators, spies operating in Ukraine, and Russian forces present outside of Kiev during the invasion.

US security companies and officials remain vital partners in Ukraine’s efforts to defend against Russian cyberattacks, which have persisted since at least 2015. Illia Vitiuk, head of the Department of Cyber Information Security in the Security Service of Ukraine, noted that although the number of Russian attacks against Ukraine has increased in recent years, they have become more targeted in recent months.