The murders in Moscow of a top Russian general and his aide shine the spotlight on an obstacle that Donald Trump’s Ukraine envoy will face when he visits Kyiv in two weeks. Operating in the  shadows, deep inside Russia, Ukrainian agents increasingly murder officials and officers they deem “war criminals.”

On Wednesday, Russian authorities announced they had detained a suspect in the killing, and the suspect was said to be an Uzbek citizen who was recruited by Ukrainian intelligence, the Associated Press reports.

Among many tasks facing Mr. Trump’s envoy, Keith Kellogg, a retired lieutenant-general, will be to fashion a political settlement that will bring these Ukrainian agents in from the cold. Otherwise, an Irish Republican Army-style terror campaign could continue for years. 

In Tuesday’s attack, a shrapnel-filled bomb brought down two men: Lieutenant General Igor Kirillov, who was in charge of Russia’s nuclear, biological, and chemical protection forces, and his assistant, Ilya Polikarpov. The day before Ukraine’s State Security Service, or SBU, accused the Russian Army general of the “massive use of banned chemical weapons” in Ukraine.

Ukraine charges that Russia uses a World War I-era toxic choking agent, chloropicrin, to flush Ukrainian soldiers out of their trenches. Kyiv blames General Kirillov for using  banned chemical weapons on 4,800 Ukrainian soldiers, causing the hospitalization of more than 2,000. Two months ago, Britain sanctioned Russia’s chemical troops “and its leader Igor Kirillov, responsible for helping deploy these barbaric weapons.”

General Kirillov, a familiar face on Russian state television talk shows,  is the most senior Russian military officer to be assassinated inside Russia. Yesterday, a former president, Dmitry Medvedev, told a televised meeting that Moscow will avenge his murder.

“Law enforcement agencies must find the killers in Russia,” said Mr. Medvedev, now a security official. “Everything must be done to destroy the masterminds who are in Kyiv. We know who these masterminds are. They are the military and political leadership of Ukraine.”

One admitted mastermind is Ukraine’s military intelligence chief, Kyrylo Budanov. Eighteen months ago, he pledged to “eliminate Russian war criminals anywhere in the world.” One month earlier, a Russian woman killed pro-war blogger Vladlen Tatarsky by handing him an explosive-filled bust.

This fall, Ukraine’s assassination campaign appears to have gone into high gear. Largely unreported in the Western press, the individual killings add up to state policy. Here are  highlights:

• On September 27, Russian partisans in coordination with Ukrainian military intelligence shot to death the director of a Russian Defense Ministry drone division, Colonel Aleksey Kolomeitsev. The killing took place at Kolomna, a city in the Moscow Region, the Kyiv Independent reported.
• On October 17, also in the Moscow region, a gunman fired three shots through the car window of a Russian military intelligence officer, Nikita Klenkov, killing him instantly, Reuters said. He had returned the week before from the war zone where he trained Special Operations Forces.
• On October 18, a car bomb killed Major Dmitriy Pervukha of the Russian Army, at Russia-controlled Luhansk, the Kyiv Independent reported. Ukrainian military intelligence said only that he was involved in “war crimes.” He was killed at the center of Russian-occupied Luhansk after his car exploded, Ukraine’s military intelligence said  October 19.
• On October 20, the body of a senior Russian pilot, Dmitry Golenkov, was found in an orchard with fatal hammer wounds to the head, Newsweek reported. According to Ukrainian military intelligence, he had been involved in a June 2022 rocket attack on a shopping mall at Kremenchuk, Ukraine. With the mall packed with shoppers on a holiday weekend, the toll was 22 dead and 59 injured. Ukrainian military intelligence said the pilot later carried out “a rocket attack on a residential building in Dnipro on January 14, 2023, when 46 Ukrainian civilians died, including 6 children.”
• On November 13, a car bomb killed a Russian Navy captain,  Valery Trankovsky, at Sevastopol, Crimea, headquarters of Russia’s Black Sea fleet. A Ukrainian State Security Service official told the Kyiv Independent that the captain was a “war criminal who has ordered cruise missile launches from the Black Sea against civilian sites in Ukraine.”
• On December 9, a car bomb killed the chief of Olenivka prison colony, Sergey Yevsiukov, the BBC said. He was widely held responsible for the 2022 massacre of up to 62 Ukrainian POWs in a camp explosion in Russia-occupied Donetsk. In Ukraine, he faced charges for war crimes, including torture and delaying medical aid to prisoners.
• On December 12, a gunman shot dead Mikhail Shatsky, a scientist seen as the brains behind incorporating AI technology into Russia’s Kinzhal, or Dagger, cruise missiles. The Kyiv Independent reported that he was found dead in the snow at Kuzminsky Forest Park, eight miles from the Kremlin.

Complicating detective work for Russian investigators, there is now a nationwide network of radicalized Russians committed to working with Ukraine to attack the Putin regime. Known as Rospartisan, they post news and videos of their attacks on a Telegram channel. 

Ukrainians — or radicalized Russians — show little interest in easing their terror campaign. Yesterday, a few hours after the successful assassinations of General Kirillov and his aide, a caller reported a bomb placed under the car of  the chairman of the Duma Defense Committee, Andrey Kartpolov. Explosives experts searched the car, parked on Ruzheyny Lane, two miles from the Kremlin. They did not find anything, Moscow news sites reported.

Around the same time, at the Duma, its chairman, Vyacheslav Volodin held a moment of silence for General Kirillov,  describing him as “not only a military leader, but first and foremost a scientist.” Last Thursday, a Ukrainian court had sentenced Mr. Volodin to 15 years in absentia for preparing the legal framework for Mr. Putin’s 2022 invasion of Ukraine.

To date, Ukrainian courts have convicted 138 Russians, almost all in absentia, for war crimes in Ukraine. Some of these convictions have proved to be preludes to assassinations.