David Kozák

David Kozák (12 August 1999 – 21 December 2023) was a Czech mass murderer and postgraduate student at Charles University. He is responsible for the 2023 Prague shootings in which he attacked the Faculty of Arts in Prague, and killed a man and his infant daughter in Klánovice six days prior. Kozák also murdered his own father prior to attacking the university. After the shootings, he killed himself just before police reached him.

Biography
Kozák was born in the Czech Republic on 12 August 1999. Little is known about his early life, apart from the fact that he lived in the village of Hostouň, about 9 kilometers west of Prague. Sometime after graduating high school, Kozák began studying history at Charles University in Prague. Specifically, he was studying history of Poland and earned a bachelor's degree in history and European studies.

Kozák successfully defended his bachelor's thesis at the Institute of World History, Faculty of Arts, Charles University, entitled The Antagonism problematics of Galician Peasant Revolt and Kraków Uprising in the year of 1846. The supervisor was professor František Stellner; the thesis was defended with an excellent grade. Kozák was subsequently awarded the Marian Szyjkowski Award.

Mental state
Czech Police Chief Martin Vondrášek said that the perpetrator had a gun license and owned eight firearms. As a European Union member state, the Czech Republic adheres to the European Firearms Directive and legal accessibility of firearms is comparable to other EU countries. In 2021, a constitutional amendment to the country's Charter of Fundamental Rights and Freedoms codified the citizens' the right to defend themselves or others with a weapon. To legally possess a firearm in the Czech Republic, a person must first obtain a firearms license, which requires, among other things, a medical examination, A bill of health is issued by the general practitioner, who can also request a review of the applicant's mental state.

Kozák's friend, who has been named only as "Alice" by the media, became worried about his mental state in summer 2022. Due to her intervention, Kozák underwent four visits with a psychiatrist between September and November 2022. Here, Kozák disclosed first suicidal thoughts, but during the visits progressed towards also murderous ideas aimed at his parents as well as unassuming other people. The psychiatrist advised that Kozák starts visiting a psychologist, which he did only once in December 2022. Psychiatrists in the Czech Republic are bound to send their medical reports to the patient's general practitioner, "if the practitioner is known to them". As Kozák didn't disclose name of his general practitioner, no report was sent.

The general practitioner could have learned about Kozák's psychiatric visits from an online database of the patient's medical prescriptions. However, reviewing this information is not obligatory and the general practitioner that issued the bill of health failed to do so. The only information in the bill of health for the gun license was that Kozák must wear glasses when using firearms.

According to police ordered post-mortem psychological evaluation, Kozák had personality that was "schizoid with narcissistic and antisocial traits and a very solid IQ", but did not suffer from any particular mental disorder.

Planning of attack
Police concluded that Kozák had been planning to conduct a mass murder for a long time. He researched information about mass murderers, including the "Forest Killer". In September 2023 he limited his planning to the University and its vicinity. He researched teaching schedules of the fourth floor classrooms and downloaded floorplans both of the building where he attacked as well as the other school building at the Celetná street. He made notes of probable number of students in each of the classrooms. He was further researching public events at the nearby Rudolfinum building, Jan Palach square and other locations at the Prague Old Town.

Kozák received a gift of CZK 300,000 (approximately USD 13,000) from his grandmother and liquidated CZK 400,000 (USD 17,000) from a long-term savings account. This money as well as income from his airport job was used towards purchases of firearms and ammunition.

Kozák had told several friends about his gun purchases. He shared most information with his friend Alice, whom he informed also about undergoing shooting courses. On 3 November 2023, the perpetrator told Alice that he started exercising as he will have to carry heavy bags in a month or two. On 6 December 2023, Kozák wrote messages to Alice, which according to the investigators show clear determination to commit a murder.

Murders
On 15 December 2023, Kozák is believed to have murdered a 32-year-old man and his two-month old daughter in the Klánovice Forest in Prague. The motive for the killings is currently not known. However, some have pointed out that the case is similar to the murders committed by Viktor Kalivoda in 2005, wherein he murdered three random people in preparation for a mass killing in Prague. After the murders, Kozák was one of about 4,000 different suspects in the case, though police were unable to prevent the subsequent attack.

Six days later, on 21 December, Kozák murdered his father at his home in Hostouň before travelling to the Faculty of Arts, Charles University main building in Prague. There, he opened fire on students and faculty inside the building, killing 14 people and wounding 22 others. Kozák also fired at police and bystanders from the fourth-floor balcony, wounding three of them. After being engaged by a police officer, Kozák committed suicide by shooting himself. The entire attack lasted about 20 minutes.

Shortly after the attack, police searched his home and found a letter in which he confessed to the murders in Klánovice. Improvised explosive devices were also found in his home. The police investigators based his motive to be the revenge to the society as the attacker felt misunderstood. The shootings are the deadliest mass murder in Czech history, surpassing the 2015 Uherský Brod shooting.