As the war in Ukraine rages on, law enforcement authorities around the world are moving to impose accountability for Russian atrocities.

Trials of Russian soldiers accused of war crimes began last year in Kyiv. In March, a U.N. report said Russia has committed war crimes and possibly crimes against humanity, while the International Criminal Court charged President Vladimir Putin with war crimes for the abductions of Ukrainian children and issued arrest warrants for him and a top adviser. Ukrainian officials say the Russians are responsible for nearly 100,000 atrocities since the conflict began.

In June 2022, the U.S. Department of Justice launched a team dedicated to prosecuting war crimes in Ukraine, led by Eli M. Rosenbaum ’80. Nicknamed “the Nazi hunter,” Rosenbaum spent much of his 40-year career at DOJ pursuing and prosecuting Nazis living in the U.S., racking up 119 court victories, more than the prosecutors in all other countries combined. Since 2010, he has been director of human rights enforcement strategy and policy in DOJ’s Human Rights and Special Prosecutions Section.

In April, Rosenbaum discussed the scope of Russia’s crimes and the difficulties of prosecuting the perpetrators in the middle of a conflict. The interview has been edited for clarity and length.

Why did Attorney General Merrick Garland establish this team just a few months after the war began, and why did you agree to lead it?

I think his motivation was shock and revulsion over what Russia was doing in Ukraine. It clearly touched his heart and he realized that at the Department of Justice, we have all kinds of resources that could be mobilized to assist the people of Ukraine. I and my colleagues have been working on human rights enforcement for some decades.

While I was at the law school, I started reading about a scandal that had been exposed in the late ’70s, that there were Nazi war criminals in America. In the fall of my second year, I saw a blurb that they had just opened a special unit at the Justice Department to investigate and prosecute, where possible, Nazi cases. I thought, “That’s the summer job for me.” I called directory assistance and got the main number for the Justice Department that night, and then I got the number for the person in charge of the unit. I called, and by the end of the conversation, I had the job. I fell in love with the people doing the work, and the work was just so fascinating and important to me. That’s how I ended up doing this, and it’s been really one of the two greatest experiences of my professional life.

How does the war in Ukraine compare with other conflicts historically?

This is the largest-scale perpetration of war crimes and crimes against humanity in armed conflict since World War II.

Even though the war is just over a year old? 

That’s right. That’s how widespread, systematic, and ghastly this is. The Ukrainian authorities have already registered, to use their parlance, over 90,000 atrocity crimes, and many of those have multiple fatalities. There are areas where war crimes have taken place, probably in large numbers, they haven’t liberated yet, so we don’t know how many victims or how many crimes there have been.

What types of war crimes appear to be most common?

It’s a broad range of crimes. It’s rape; it’s torture; it’s abduction of children; it’s intentional destruction of civilian infrastructure, including residences. It’s killing of prisoners of war and killing of captured civilians. Those are probably the main ones, so far. There are also environmental war crimes. No case of an environmental war crime has ever been prosecuted in the history of law, but the concept has existed. There’s been massive damage to the Ukrainian environment. The Ukrainian prosecutor general’s office, with which the U.S. Department of Justice has worked very closely, is exploring the possibility of bringing the first-ever prosecution for an environmental war crime. And we are helping them. They don’t have a lot of experience prosecuting environmental crimes at all, much less environmental war crimes. But we have a lot of experience prosecuting criminal cases involving environmental damage, so we have provided training to our Ukrainian colleagues, and we brought in the Environmental Protection Agency because they have the best environmental lab in the world and have a lot of experience collecting and preserving evidence of environmental crimes.

What authority does the U.S. have to prosecute war crimes committed by foreign actors in another country?

Until Jan. 5 of this year, we were limited to war crimes committed against U.S. nationals or by U.S. nationals. Reacting to the carnage brought by Russia in Ukraine, Congress passed a law expanding jurisdiction under the federal crime statute called the Justice for Victims of War Crimes Act. That gave us jurisdiction over any war criminal from any conflict who is present in the U.S.

One lesson we know from World War II and ensuing conflicts is that, eventually, some perpetrators of Russian war crimes will come to the U.S. We don’t want to make the mistake of not being as alert as possible and not being ready for these people.

It is very challenging to do this when the war is still underway. The Russian government is in possession of lots of incriminating information. Obviously, they’re not going to assist us. There are, on the other hand, some advantages that we have. So much is communicated electronically, and therefore, can be intercepted — I’ll just leave it at that. I would say also, the U.S. government has had eyes on Moscow’s military since the ’40s, since it was the Soviet Union, and we have access to information of that nature.

The International Criminal Court has charged Russia with war crimes and issued arrest warrants for Russian President Vladimir Putin and one of his advisers. How does your work intersect with theirs, given that the U.S. is not an ICC member?

The U.S. government supports what the ICC supports. In December, Congress enacted an exception to the American Servicemembers Protection Act of 2002. That’s a bill Congress passed not long after 9/11 barring the U.S. from assisting the International Criminal Court in any way. Over the years, Congress has enacted some exceptions. In the ICC’s investigation in Ukraine, there is still some discussion within the U.S. government about doing that.

If your team came upon information that’s helpful to the ICC’s case against Putin, it’s not clear that you’d be able to share that with the ICC?

All I can say is, stay tuned. I’m working on how best to assist the ICC. We have assisted the ICC on other matters in prior years, so this is not a radical departure from U.S. practice. But we have to work out the best modus operandi for assisting the ICC on its Ukraine investigations.

This article originally appeared in the Harvard Gazette.