On July 4, 1990, less than four months after he walked out of Leopoldov prison, Jozef Slovák took sixteen-year-old Monika Ondíková, from Moldava nad Bodvou, whom he had met in Prague, out to the Konopiště estate near Benešov, about fifty kilometers southeast of the capital. In the manor park he pulled a gas pistol and fired it at her eight times with nerve-agent rounds. When she fell he beat her on the head with a stick until she was dead. He went through her things and took 2,400 US dollars, 800 German marks, more than 16,000 Austrian schillings, a ring and her makeup, dragged the body deeper into the woods and covered it with branches. A week later he went back and put a train ticket for České Budějovice in her pocket to send the police the wrong way.
He should not have been free. In August 1978 he had met a twenty-one-year-old Yugoslav woman, Blažica P., on a train and offered her somewhere to stay in Bratislava. On August 22 he took her into the woods at Železná studnička, on the edge of the city, and tried to have sex with her; when she refused and fought him he choked her to death, dragged her deeper into the forest, covered her with branches, burned some of her clothes on the spot and gave some of her belongings to his girlfriend. In 1982 he was sentenced to fifteen years. On March 10, 1990, he was released on probation under the sweeping amnesty declared by President Václav Havel, which emptied much of the country's prisons at once. Without it he would have stayed inside until 1997. Of all the cases raised in Slovakia against that amnesty, his is the one cited most.
He was born on April 7, 1951, at Plavecký Štvrtok in western Slovakia, and was sent to prison eight times in his life. Slovak accounts describe a man of well above average intelligence who read constantly and got into conversation with strangers easily, which was how he found the women. Court psychiatrists assessed him as a psychopathic personality.
Seventeen days after Konopiště he killed Vladislava Maříková, eighteen, from Cheb, whom he had met on the train from Plzeň to Bratislava.
Two more women followed in 1991, Diana Lopuchovská and Anna Královičová. The last of them was killed in July 1991 and found at Železná studnička, the same wood as his first victim thirteen years before. She fought him. When he was arrested in Bratislava two days later, he still had the bruises she had left, and police found an illegal gun.
The four killings of 1990 and 1991 were investigated by Jozef Vachálek of the Slovak police. Vachálek has said that Slovák came to trust him and confessed because, in Slovák's words, he was the only one who had not asked him about nonsense, and that he then talked about other victims and showed officers, of his own accord, where he had left them. The two men have stayed in contact for decades.
On August 20, 1993, the city court in Bratislava sentenced him to life for the murders of Monika Ondíková, Vladislava Maříková, Diana Lopuchovská and Anna Královičová. He is serving it at Ilava. In 1997 he complained to officials of the town that he could not create new inventions in electronics for want of tools and a typewriter. Slovak accounts put his victims at no fewer than five, and the investigator's references to further victims have never been tested in court.