National flags on public buildings were at half-staff and people across the Czech Republic are set to observe a minute of silence as the country holds a day of national mourning on Saturday to honor the victims of the worst mass killing in Czech history.

The shooting inside a university building at the heart of the Czech capital on Thursday left 14 dead and dozens injured.

Police and prosecutors said they have evidence the 24-year-old shooter also killed his father earlier in the day and a man and a baby in Prague last week.

Bells will toll at churches at noon and a Mass at St Vitus cathedral in Prague, the biggest in the country, will be celebrated for the victims. President Petr Pavel is scheduled to attend the service that is open to everyone.

Similar religious services will be held in other cities and towns, while Christmas markets in a number of places were closed or reduced their programs amid boosted security measures.

Authorities said that 13 people died at the scene in the Faculty of Arts of Charles University and one died later in a hospital. A total of 25 people were wounded, including three foreign nationals.

Milos Vystrcil, speaker of Parliament’s upper house, the Senate, was among many who have been coming together to light candles at an impromptu memorial for the victims created in front of the university headquarters.

“It’s been a horrible experience for us all but it still can't be compared with what the victims had to experience at the time of the attack and what their dear ones have to experience now,” Vystrcil said.

“I think that to help them at this point we express our support and that's what we're all doing now.”

The 14 who died have been identified and their names have been gradually released.

The university confirmed two staff members were among them, including the head of the Institute of Music Sciences, Lenka Hlávková. First-year student Lucie Spindlerova was another, said the Lidove noviny daily, where she also worked.

The shooter, who killed himself as police closed in, was Czech and a student at the Faculty of Arts .

Investigators do not suspect a link to any extremist ideology or groups. Officials said they believed he acted alone. His motive is not yet clear.

Previously, the nation’s worst mass shooting was in 2015, when a gunman opened fire in the southeastern town of Uhersky Brod, killing eight before fatally shooting himself.