Kot was accused of two murders, four attempted murders, six poisoning attempts and four counts of arson.
The trial aroused great interest amongst the public, who demanded he receive the death penalty.
During visits to the crime scenes, and during the court hearings, Kot smiled, and looked like good-natured boy and when weapons or detailed descriptions were presented to the court, he visibly cheered up.
He was relaxed and seemed unaware of the possible sentence he would receive.
Problems soon emerged when it came to assessing his mental state at the time of the offences.
Two teams of experts were consulted, whose opinions of Kot’s sanity differed.
Forensic experts from Krakow found Kot to be a psychopath with a ‘deviation from the norms of temperament, drive and character, coupled with a lack of higher emotionality’.
They presented to the court that Kot was a limited sanity murderer who could not adapt to social norms.

In turn, psychiatrists believed that Kot was aware of the harmful effects of his actions and was even able to control them.
Elements of the crimes such as his ability to refrain from attack in certain circumstances, helped to sustain their theory of Kot’s overall sanity.
Consequently, the court upheld the opinion of the psychiatric experts and found Kot guilty, condemning him to the death penalty.
As Kot was only sentenced for the murder of the 11-year-old boy, his lawyers filed an appeal to the Supreme Court, who then also took into consideration the testimony of the forensic experts along with Kot’s young age and overturned the death penalty ruling and instead sentenced Kot to life imprisonment.
The General Prosecutor of the Polish People's Republic, however, had the right to revise the sentence and in March 1968, reconvened the Supreme Court.
Once again Kot was sentenced to death by hanging.
The judgment of the Supreme Court was based on the cruel murder of the 11-year-old boy and Kot’s attempt to kill the 7-year-old girl, stating:
“Taking in to account, the defenseless beings, his cynicism and lack of remorse, the only right punishment is the death penalty”
Kot was executed on 16 May 1968.
An autopsy of Karol Kot showed that he had been suffering from a previously undiagnosed large brain tumour.