Could social media hold evidence of alleged Russian war crimes?

A driver's-eye-view as a car weaves down a street strewn with bodies. Corpses burned almost beyond recognition. Bodies of men and women, some with their hands bound, half-buried in the dirt of what appears to be a mass grave.

These scenes of mutilation and death, posted to social media and rapidly shared many thousands of times, could hold crucial clues for investigators probing alleged war crimes by Russian soldiers in the Ukrainian city of Bucha. The mounting evidence of widespread civilian deaths in the city just northwest of Kyiv has incited global outrage and harsher sanctions against Russia, who began its invasion of Ukraine on Feb. 24.

In March, International Criminal Court prosecutor Karim Khan said he was opening an investigation into possible war crimes in Ukraine.

"Social media has completely transformed the way human rights investigations happen," said Yvonne McDermott Rees, a professor who specializes in international criminal law at the Hillary Rodham Clinton School of Law at Swansea University.

With just a simple search on platforms like Twitter, Facebook, TikTok and Telegram, investigators can access a "phenomenal" amount of information — often in regions they otherwise couldn't reach due to fighting, McDermott Rees said.

But it takes more than just a tweet — or even thousands of them — to prove a war crime. 

Those posts are only a starting point for investigators, who are also in a race against time, as social platforms' moderators remove content that violates their policies — potentially deleting that evidence forever.

The use of video as evidence in war crimes prosecutions isn't new. 

Black and white footage, filmed by Allied troops as they liberated Nazi concentration camps, was used as evidence at the Nuremberg Trials in 1945.

Similarly, a video of a mass execution of Bosnian Muslim men in 1995 — part of the Srebrenica massacre, in which thousands of Bosnian Muslim men and boys were executed — shocked the world when it was revealed during the trial of former Serbian president, Slobodan Milošević, a decade later.

But legal experts say the near real-time access that social media offers is a game-changer.

"[In previous conflicts], you were often trying to find those rare pieces of video footage that might exist, or photographs that people had taken. And you might be going door to door, knocking on doors, literally, to try and capture that information," said Alexa Koenig, executive director of the Human Rights Center at U.C. Berkeley School of Law.

"Today, with the prevalence of information posted to social media … it's really finding the signal through the noise."

Social media has already played a role in a handful of war crimes convictions under domestic laws in Germany, Finland, the Netherlands and Sweden, involving individuals who fought in Syria and Iraq, according to Human Rights Watch. In some of those cases, the criminals were photographed posing with the bodies of enemy combatants, and the photos were then uploaded to Facebook.