Due to trial evidence and to the seemingly random choices of victims, which included children and elderly people, Kot was nicknamed the Vampire of Kraków (Polish: Wampir z Krakowa).

For family summer holidays, the four would travel to Pcim, to the south of Kraków, where a bored Kot began to regularly visit a butcher shop and became increasingly fascinated by knives, dying animals, and blood.

[3] Kot found pleasure in watching death and, at the encouragement of some of the abattoirs, in drinking still-warm pig's blood.

[citation needed] Academically, Kot had no problems at school, although he remained isolated from other students because of his somewhat strange personality.

On 13 February 1966, in an overkill, Kot fatally stabbed an 11-year-old boy, Leszek Całek, near Kościuszko Mound, where a toboggan contest for children was being held.

During the trial, expert witnesses stated that the amount of arsenic used by Kot was sufficient to kill anybody who would drink the beverage.

He was arrested on 1 June 1966, the day after his matura exam, which he was allowed to sit in order to prove that he was sane so that he could not later plead insanity during a trial.

[3] On 3 June, Kot had his first formal interview, and on 6 July, in a police lineup, he was identified by Velgen, the woman he stabbed inside the church.

After a series of psychological observations and examinations, the doctors asserted that he was completely sane and could attend the trial with full consequences of his actions.

When asked in an interview[8] whether he was aware of the notion of murder being a crime and an evil deed, Kot presented his moral standards.

According to him, what determines the moral appropriateness of human actions is the fact that they bring an individual satisfaction and a sense of fulfilled duty; he, therefore, considered himself a murderer, but not an evil person.

[9] Kot seemed unfazed by the fact that he would die, saying "The pleasure I felt when the knife was cleaving the meat… It’s impossible to describe the feeling.

"[2] The killings were recreated for Episode 2, Season 1 of the show Killers: Behind the Myth called "Kot: The Vampire of Crakow", which aired in March 2014.