The 24-year-old Charles University student shot 13 people in a university building near the famous Charles Bridge in Prague’s Old Town on Thursday afternoon and then killed himself. One injured person later died in hospital. The bloody act caused horror across the country’s borders.

“We all try to create heaven on earth, but the reality of life shows us that evil exists,” Prague Archbishop Jan Graubner said at mass in St. Vitus Cathedral. Students from the Faculty of Arts at Charles University brought white roses to the altar for the victims.

“Each person’s life, in its uniqueness, enriches the lives of others and becomes a part of it. His loss is therefore irreplaceable,” said Charles University Rector Milena Kralickova.

A choir that sang at the mass was led by musician and lecturer David Eben from the Musicology Institute. The 49-year-old institute director and mother of two, Lenka Hlavkova, is among the 14 fatalities.

Czech Prime Minister Petr Fiala had already visited an improvised memorial site in front of the university on Friday, where students and other mourners set up hundreds of candles. It was difficult to find the right words to condemn the act and at the same time “to express the pain and sadness that our entire country is feeling in these days before Christmas,” said Fiala.

According to police, the shooter was a lone perpetrator. He was not known to the police, but according to investigators he had a “huge arsenal of weapons and ammunition.” The 24-year-old is also linked to the death of his father, whose body was discovered shortly before the gun attack at the university in the town of Hostoun, west of Prague.

According to police chief Martin Vondrasek, the police launched a search for the 24-year-old after the father’s body was found. He had therefore announced in a note that he wanted to kill himself in Prague.

The police then searched the main building of the Faculty of Philosophy, assuming they would find the 24-year-old giving a lecture there. However, the shooter had entered another faculty building. At around 3 p.m. the police received the first information about shots fired. According to Vondrasek, the rapid reaction force was on site within twelve minutes. The shooter’s body was found around 3:20 p.m.

The 24-year-old is also suspected of killing a young man and his two-month-old daughter while they were walking in the forest in a Prague suburb on December 15th. A ballistic analysis showed that the weapon used in the forest was “identical” to a weapon “that was found in the university shooter’s house,” the police wrote on the online service X (formerly Twitter).

Police have arrested four people since the attack at the university because they either threatened to copy the crime or encouraged it. The police will increase security in some places, including several schools, until at least the New Year.