KHERSON, Ukraine — To reach the dank, eerie basement were the Russian police detained Ukrainian civilians required navigating a crumbling concrete stairway into a dark abyss below.
The site still reeked of smoke from a fire. Plastic zip ties used for binding hands were scattered around the hallway, along with yard-long sections of plastic and metal pipe — evidence, Ukrainian war crimes investigators said, that the basement had been a site of torture and abuse.
When headlamps swept over the walls of the chamber, dozens of drawings came into view, scratched into the soft plaster of the walls. Some were crude pictures of houses; others marked the names of people detained, or recorded the number of days they had spent there.
The site in an unassuming office building in the center of Kherson was a secret detention center for the Russian Security Services, a successor agency to the K.G.B., Ukrainian prosecutors said on Wednesday.
The liberation of Kherson last week was largely a jubilant affair. After months of bloody combat, the Russians withdrew from the southern city without a fight. A crowd poured into a central square and when Ukrainian soldiers arrived, women hugged them and men hoisted them into the air.
A darker side emerged Wednesday: torture chambers. Ukrainian prosecutors fanned out in seven teams for a first day of investigating war crimes in the city, and by afternoon said they had found 11 detention centers, including four sites they believed the Russians used to hold and torture civilians.
The grim pattern of abuses evident in other areas liberated from Russian occupation had been repeated in the southern city of Kherson, prosecutors said. Sites of interest had been identified months ago by interviewing people who had left the city for other parts of Ukraine.
No bodies or mass graves have been discovered in Kherson, but investigators found multiple sites with signs of extrajudicial detention, and indications of abuse in basement prisons.
“We knew this place existed and we were looking for it,” said a Ukrainian intelligence officer, who insisted on anonymity because he was not authorized to speak publicly. He showed the detention area under an office building to New York Times reporters on Wednesday, shortly after demining experts swept the building for mines and booby traps.
The State of the War
- Explosion in Poland: A blast that killed two people in Poland near its border with Ukraine was most likely an accident caused by a Ukrainian defense missile, Poland’s president and NATO said. The explosion heightened anxieties on a day of broad Russian strikes in Ukraine.
- Retaking Kherson: On Nov. 11, Ukrainian soldiers swept into the southern city of Kherson, seizing a major prize from the retreating Russian army and dealing a bitter blow to President Vladimir V. Putin. Days after the liberation, signs of torture are emerging.
- Winter Looms: Many analysts and diplomats have suggested there could be a pause in major combat over the winter. But after pushing the Russians out of Kherson, Ukraine has no desire to stop.
- Beta Testing New Weapons: Ukraine has become a testing ground for state-of-the-art weapons and information systems that Western officials predict could shape warfare for generations to come.
A different detention center in Kherson was not accessible to reporters because investigators were still demining it. At this location, residents told prosecutors, the smell of decomposing bodies had been wafting about for days, though it was unclear what would eventually be found.
“The Russians could come to a home for a search, accuse a person and bring them to a police station, where they would start the torture,” Mary Okopyan, deputy minister of interior, said at a news conference in Kherson on Wednesday. She described it as “psychological and physical.”
“We are trying to collect as much evidence as possible to open criminal cases,” Ms. Okopyan said.
Russian forces detained three categories of civilians, Andriy Kovalenko, a prosecutor in the Kherson regional prosecutor’s office, said in an interview.
They arrested people suspected of being pro-Ukrainian underground guerrillas, he said. They also arrested relatives of Ukrainian soldiers, to unnerve those fighting the war, as well as government employees who declined to take jobs in the occupation administration, he said.
Prosecutors have already collected testimony on more than 800 detentions by the Russians in the Kherson region, Mr. Kovalenko said. The most common type of abuse was electrical shocking and beating with a plastic or rubber nightstick, he said.
Russian jailers would alsoplace a gas mask over prisoners’ heads and pinch off the breathing hose, he said. That technique, previously documented in other occupied areas of Ukraine, is common in prisons back in Russia, to the point where it has acquired a nickname: “the little elephant.”
Torture in pretrial detention and in prisons in Russia is widespread and has been documented by rights groups for most of the post-Soviet period.
Ukrainian prosecutors say they are gathering evidence of torture in areas of Ukraine occupied by the Russian army since the invasion in February for what they hope will eventually become an international criminal proceeding.
At all the sites in Kherson, Ukrainian soldiers found the cells empty. The Russians had released some detainees and took others along with them on their retreat, Mr. Kovalenko said.
Across town from the office building, Ukrainian officials showed reporters another site of suspected abuse, a pretrial detention center the Russians had used to hold political prisoners. The center had served as a jail in Ukraine’s criminal justice system before the war.
Inside, a portrait of Vladimir V. Putin had been taken off a wall and set on a chair, the glass shattered.
The cells were littered with plastic water bottles, fetid heaps of bedding and filthy clothing. In one cell, electrical wires with the insulation stripped off at the ends snaked along floor, suggesting possible abuse with electrical shocks.
Elsewhere in Kherson, the Russians had detained civilians in basements of private houses or businesses. At the office building, for example, nothing on the exterior hinted at the horrors in the basement. Signs on the building suggested that before the war it had housed an insurance company, a dance studio and a bank.
Ruslan Paklov, the building superintendent, said in an interview that soldiers in ski masks had turned up in May and ordered the office workers to leave.
“They said, ‘A new government is here and we will use this building,’” Mr. Paklov recalled. He learned of the basement prison only in recent days, after the city’s liberation. “This is just terrible,” he said.
Russian jailers had screwed heavy iron latches into six chambers where prisoners were held, while another chamber had no lock. This was the room for interrogations and abuse, said the intelligence officer, who had interviewed former detainees before arriving at the site.
The concrete floor was covered in soot and the footprints of boots. Only a bare desk remained; the metal pipe and gas masks, the possible instruments of abuse, were found elsewhere, the officer said.
The etching on the walls were striking: times, dates and names of detainees.
In one place was a depiction of what appeared to be a Ukrainian village house, scratched into the plaster.
The Ukrainian intelligence officer suggested that a prisoner had drawn his home on the cell wall to pass the time or perhaps cheer himself upin this glummest of places.
In one place, one word in Ukrainian had been scratched into the wall: “Freedom.’’