David Kozak went on a killing spree at Charles University on Thursday.

At least 14 people were killed, and 25 others sustained injuries in a mass shooting at the Charles University in Prague, Czech Republic, on Thursday. According to Czech police, the incident occured in the philosophy department of the varsity. Authorities are investigating what’s been described as the worst mass shooting in the history of the Czech Republic. The death toll may rise, they said.

The police said that the shooter, David Kozak, was a twenty-four-year-old history student.

Who was David Kozak?

David Kozak, 24, lived in a village almost 20 km outside Prague and was getting his Masters Degree in Polish History at Charles University. He was an “excellent student”, Prague Police Chief Martin Vondrasek said.

He legally owned several guns and was heavily armed during the incident. The Police Chief said what he did was a “well thought out and horrible act.”

David Kozak is suspected to have also killed his father in the nearby town, Houston, before going on a killing spree in Prague. He did not have an accomplice, according to the police.

Police found Kozak’s body inside the university but it was unclear if he killed himself or was shot by officers.

David Kozak talked about planning a school shooting on the messaging app Telegram, treating his channel there like a “diary” of his life “before the shooting.” “I want to do school shooting and possibly suicide,” he wrote in a post, as per the Telegraph, adding, “I always wanted to kill. I thought I would become a maniac in the future.”

He is also suspected of shooting and killing a father and a newborn baby just one week before carrying out his murderous rampage, as per AP.

Police provided no information about the victims or a potential motive for the shooting. Czech Interior Minister Vit Rakusan stated that investigators do not suspect any connection to extremist ideologies or groups.

Charles University authorities have announced that they will increase security measures in university buildings immediately. They said in a statement, “We express our deepest condolences to all the bereaved families who lost their loved ones. Our thoughts are now with the loved ones of those who are now fighting for their lives.”