Early on July 29, on the outskirts of Olenivka village in eastern Ukraine, a mysterious explosion tore through a separatist-controlled prison housing hundreds of Ukrainian detainees. The blast killed at least 50 people, according to Russian officials, including fighters who surrendered to Russia in May at the Azovstal steel plant in Mariupol.
Both sides have blamed each other for the massacre — a potential war crime. And Russian and separatist officials, from the self-proclaimed Donetsk People’s Republic, where Olenivka is located, have barred independent investigators from reaching the site.
Russia’s Defense Ministry claims that Ukrainian forces caused the blast using a U.S.-supplied rocket launcher known as HIMARS (High Mobility Artillery Rocket System), in a strike meant to prevent fighters from giving up information.
But available images of the destroyed building at the prison appear inconsistent with a HIMARS-launched attack, according to six experts The Washington Post consulted. The experts could not definitively say what caused the damage, but they pointed to a lack of shrapnel marks and craters and only minimal damage to internal walls in the available visuals of the aftermath. Instead, there were visible signs of an intense fire, which is at odds with damage caused by the most common HIMARS warhead.
Satellite imagery appears to show recent physical changes to the complex, and former detainees told The Post they were previously housed in a different area from where the blast occurred. Ukrainian authorities claim that a deliberate transfer of fighters to a new housing area, which was ultimately the area damaged in the blast, demonstrates that Russian forces had planned an attack.
Here is what we know about what happened at Olenivka prison on July 29.
What we know about the prison and its detainees
The prison camp is located just a few miles from the front line — and about 12 miles from the city of Donetsk. It is divided into two sections: one with barracks and detention facilities and the other with an out-of-use industrial zone where inmates used to work years ago, when the prison was a regular penal colony, according to former detainees who spoke with The Post.
Since May, the facility has housed several thousand people from Mariupol. Among the detainees were about 1,500 fighters from Azovstal, the ex-commander of the Ukrainian national guard’s Azov Regiment, Maksym Zhorin, told the Associated Press.
The International Committee of the Red Cross visited the facility in Olenivka twice — on May 18 “to assess the needs of prisoners of war” and on May 20, “to drop water tanks outside,” the organization told The Post. On May 19, the ICRC said in a statement that it had registered hundreds of Ukrainian prisoners of war who surrendered in Mariupol.
Ukrainian intelligence officials allege that the site of the blast had only recently been outfitted to house prisoners, a refurbishment that concluded onlytwo days before. After that, detainees from Azovstal were moved in.
Three former prisoners, released from Olenivka in July, confirmed to The Post that these locations are in the southern part of the facility, where detainees were housed. One pointed out the buildings in satellite imagery.
The blast damaged a building located north of the housing barracks — a white-roofed warehouse, attached to a longer structure. The former prisoners who spoke with The Post said it resembled parts of the industrial zone at the facility where prisoners worked in the past.
Satellite imagery taken by Maxar Technologies on July 27 shows what appear to be groups of people congregated in open areas near where prisoners confirmed they were housed before the blast, according to a senior analyst at Maxar Technologies, and Steven De La Fuente, a research associate at the Middlebury Institute of International Studies.
Satellite imagery also confirms recent changes in the area surrounding the structure damaged in the blast. In July, a barrier was put up east of the building, according to De La Fuente and Tony Roper, a freelance military analyst and blogger. The surrounding area also appeared to be cleared of shrubbery.
In a joint statement the day after the attack, Ukraine’s military, security and intelligence services pointed to “the deliberate transfer of fighters to new premises shortly before the explosion” as evidence of “the planned nature of this crime and its commission by the Russian side.”
Ukrainian authorities also claim that graves were dug in the prison complex shortly before the explosion. Imagery captured by Planet Labs satellites shows that land at the southern edge of the compound was altered beginning sometime between July 18 and 21.
A series of ground disturbances, measuring roughly 5-6 meters in length, are visible in this area in Maxar images taken on July 27. Roper and a Maxar senior analyst said the imagery alone was inconclusive, but De La Fuente said the disturbances were “reminiscent of human gravesites” at other locations during the war.
One day after the explosion, the disturbances appeared to have been partially covered.
On July 29, shortly after 9 a.m. local time, a message appeared on the Telegram account of Deputy Information Minister Daniil Bezsonov of the self-declared Donetsk People’s Republic, stating that an attack had occurred overnight at the prison, which he blamed on Ukrainian HIMARS.
Russia’s Defense Ministry then issued a statement calling the blast a “bloody provocation” by Ukraine. And on Wednesday, Russian Deputy Defense Minister Alexander Fomin said that Ukraine had carried out the attack to prevent the prisoners from giving testimony about alleged Ukrainian war crimes. Darya Morozova, a separatist official, said no Russian guards were injured.
Ukrainian defense officials have denied launching attacks around Olenivka and instead accused Russia of staging the blast to “cover up the torture and execution of prisoners” at the facility. President Volodymyr Zelensky called it a “deliberate Russian war crime.”
Based on “available data,” Ukraine’s defense intelligence agency alleged Wednesday that Russian-backed forces had spread a “highly flammable substance” which, upon detonation, “led to the rapid spread of the fire in the premises.” It did not specify the substance or present evidence. The agency accused Moscow’s FSB spy agency and Wagner Group mercenaries of involvement in the plot.
The United States believes Russia will fabricate evidence to pin the blame for the killings on Ukraine, including by planting ammunition from a HIMARS, according to a U.S. intelligence finding first reported by the Associated Press and confirmed by The Post. Russian media shared photos of what they claimed were fragments of U.S.-made HIMARS rockets at the scene.
“The Ukrainians have been sending a lot of HIMARS their way,” a senior U.S. defense official said, speaking on the condition of anonymity to brief the media, suggesting that Russians could have assembled pieces from unrelated attacks elsewhere.
Ukrainian authorities also cast doubt on the list Russia published online of those killed or injured. Andriy Yusov, an official in the Internal Affairs and Communications Ministry, said some soldiers on the list were thought to have been elsewhere at the time of the explosion.
Videos of the prison posted on the morning of July 29 by Russian media sources show signs of an intense fire. But the structure is largely intact, except for the roofing. Charred bodies of victims are visible in bunk beds and on the floor. Other bodies, showing few signs of exposure to fire, are filmed outside the building. The number of bodies visible in this initial set of videos is far fewer than the 50 Ukrainian soldiers that the Russian Ministry of Defense said were killed.
The six experts — including arson investigators, engineers and weapons analysts — warned against drawing firm conclusions about the attack. But most agreed that the available visual evidence of the aftermath did not bear the hallmarks of a HIMARS attack.
George William Herbert, an adjunct professor at the James Martin Center for Nonproliferation Studies in Monterey, told The Post that while there was some evidence of an explosion of some kind, the damage seemed inconsistent with an attack involving HIMARS, which delivers rockets without incendiary warheads.
“I don’t know how you get from an explosive — but not incendiary — warhead to a fire like that,” Herbert said. “I do see some central floor area beds blown apart or twisted from an explosion, but no signs that was a rocket warhead.”
Parts of the metal roofing on the building collapsed inward but were largely devoid of the heavy burn marks visible elsewhere. Herbert told The Post that suggested the roof was brought down after an initial explosion or fire.
“The extremely light structural damage to the walls seems incompatible with the expected effects of the standard HIMARS rocket,” analysts at the defense intelligence provider Janes wrote in an assessment conducted for The Post.
Janes also said that the elaborate operation that Russia is accusing Ukraine of undertaking would have been difficult to pull off, requiring extraordinary precision and coordination as well as real-time updates on the pattern of life inside.
If Russia was the culprit, “this would clearly be a war crime,” William Schabas, an international law professor at Middlesex University in London, wrote in an email.
If Ukraine targeted its own soldiers, as Moscow has asserted, it would most likely be “the ordinary crime of murder” rather than a war crime, Schabas said.
John Hudson, David L. Stern and Atthar Mirza contributed to this report.
The response: The Biden administration on Friday announced a new round of sanctions on Russia, in response to the annexations, targeting government officials and family members, Russian and Belarusian military officials and defense procurement networks. President Volodymyr Zelensky also said Friday that Ukraine is applying for “accelerated ascension” into NATO, in an apparent answer to the annexations.