Late on June 25, 2007, Yekaterina Ilchenko, thirty-three, was walking home in Dnipropetrovsk after having tea at a friend's apartment. Two nineteen-year-olds were out "for a walk," as Viktor Sayenko later put it in his confession. As she passed, Igor Suprunyuk spun round and hit her in the side of the head with a hammer. Her mother found her body at five in the morning. Within the hour the two men had killed Roman Tatarevich as he slept on a bench nearby, across the street from the local prosecutor's office, beating his head until he was unrecognizable. Over the next three weeks they killed twenty-one people in the city and across Dnipropetrovsk Oblast. The press called them the Dnepropetrovsk maniacs.
Sayenko was born in Dnipropetrovsk in 1988, on May 6 by most accounts (another gives March 1). He, Suprunyuk and a third friend, Alexander Hanzha, had been at school together. Sayenko told investigators that by fourteen he and Suprunyuk were both afraid of heights and of being beaten up by bullies, and that they cured the first by hanging over the railing of a fourteenth-floor balcony for hours. They moved on to torturing and killing stray dogs in the woods near their homes and photographing themselves with the bodies, some of the pictures showing swastikas drawn in blood and Nazi salutes. At seventeen Suprunyuk beat up a boy and stole his bike, then sold it to Sayenko; both were arrested but, being juveniles, not jailed. Sayenko studied part-time at a metallurgy institute and worked as a security guard. Months before the killings Suprunyuk, with the other two, had begun robbing passengers he picked up in his green Daewoo Lanos, an unlicensed taxi.
On July 1 Yevgenia Grischenko and Nikolai Serchuk were found murdered in Novomoskovsk. On the night of July 6 they killed three people in Dnipropetrovsk: Egor Nechvoloda, a young man just out of the army, walking home from a nightclub; Yelena Shram, twenty-eight, a night guard, struck on Kosiora Street with the hammer Suprunyuk kept under his shirt, the men wiping it afterward on the clothes in her bag; and Valentina Hanzha, a mother of three with a disabled husband, no relation to their friend. The next day in Pidhorodne they attacked two fourteen-year-old boys who had gone fishing. Andrei Sidyuk was killed. Vadim Lyakhov hid in the woods and survived, was at first arrested on suspicion of killing his friend, and then helped investigators draw sketches of the attackers.
On July 12 Sergei Yatzenko, forty-eight, set out from the village of Taroms'ke on his motorcycle to fill up with fuel and visit his grandson. He had recently been forced to retire after treatment for throat cancer that left him unable to speak for a time, and he had been doing odd jobs, weaving baskets and cooking for his family; he was married, with two sons and a grandchild, and looked after his disabled mother. He never arrived. His family found his body four days later near a dump in the woods. Sayenko filmed his killing on a cellphone while Suprunyuk beat him with a hammer wrapped in a plastic bag and stabbed him with a screwdriver. On July 14 Natalia Mamarchuk, forty-five, was knocked off her scooter in a wooded stretch near Diyovka and beaten to death, and two children hiding in a tent nearby gave police a description that matched Lyakhov's. More bodies were found each day to July 16. Most victims were chosen at random from those least able to fight back, children, old people, the homeless and the drunk, and most were beaten about the face with hammers and steel bars. Few were robbed. Lidia Mikrenischeva, an elderly woman, survived when her dogs barked and drove the attackers off.
A task force of more than two thousand investigators under Vasily Paskalov was sent from Kyiv. The investigation was kept secret, but sketches and lists of stolen property went to pawnshops, and on July 23, 2007, Suprunyuk tried to sell a victim's cellphone at one for 150 hryvnias. After a phone call from the shop, he and Sayenko were arrested at the register; Hanzha was arrested at home, where he flushed other phones down the toilet. The three were charged in twenty-nine incidents, twenty-one murders and eight attacks the victims survived. Sayenko was charged in twenty-five, including eighteen murders, five robberies and animal cruelty.
At trial, from June 2008 before a panel chaired by Judge Ivan Senchenko, Sayenko pleaded guilty and Suprunyuk did not. Sayenko's father, Igor Sayenko, a lawyer, took over his defense, argued that his son was psychologically dependent on Suprunyuk, and claimed that the real killers were the well-connected children of officials. On October 29, 2008, the court was shown more than three hundred photographs and two videos, including the Yatzenko recording; the defendants said they did not recognize the men in them, and the judge answered, "You are not blind." The Yatzenko video leaked onto a shock site that December. The prosecution never established a motive; reports that the pair meant to sell the films as snuff videos were rejected by the regional security chief for lack of evidence.
On February 11, 2009, the court found Sayenko guilty of eighteen murders and Suprunyuk of twenty-one and sentenced both to life imprisonment, with fifteen-year terms for robbery; Hanzha, who had taken part only in a robbery months before the killings, received nine years. The judge found that the main motive had been a desire for "morbid self-affirmation" and noted "the poverty of their emotional world, and their absence of interest in people and moral standards." Ukraine's Supreme Court upheld the life sentences on November 24, 2009. Hanzha was reported released in 2019.