By Andrew Higgins and Jenny Gross

PRAGUE – Investigators on Friday (22) were working to establish a motive for a deadly gun rampage in the centre of Prague a day earlier amid swirling questions and nationwide mourning over the Czech Republic’s worst mass shooting since the immediate aftermath of World War II.

The gunfire that erupted on Thursday (21) at Charles University turned the historic centre of one of Europe’s most serene and beautiful cities into a scene of carnage, its festive Christmas mood pierced by screams and the din of sirens. Tourists ran for safety while some students barricaded themselves inside classrooms. Others climbed out of windows, hiding on the ledge of a building.

The gunman killed 14 people and wounded 25 others before fatally shooting himself when police surrounded him on the rooftop of the building, authorities said at a news conference Friday.

The Czech Republic cancelled soccer and hockey matches — usually immovable features of the pre-Christmas calendar — and declared Saturday (23) a day of national mourning. President Petr Pavel, who has appealed for national unity, expressed gratitude for a global outpouring of support.

“My thoughts are still with families of the victims, injured and those who had to fight for their lives,” Pavel wrote on social media, adding: “No one can imagine the fear and mental strain they went through yesterday.”

No foreign nationals were killed in the attack, but one person from the Netherlands and two people from the United Arab Emirates were among the wounded, according to the Czech Foreign Ministry.

The university’s Faculty of Arts, where the shooting occurred, remained sealed off Friday morning. Mourners gathered around candles and flowers outside the building, and an overnight thunderstorm followed by morning rain added to the capital’s sombre mood.

Amid the grief were a number of unanswered questions: What drove the shooter to open fire at the university? Could more lives have been saved? And did the Czech Republic’s permissive attitude toward gun ownership play a role?

Authorities on Friday did not suggest a motive, having earlier ruled out any connection to international or domestic terrorism, but told a news conference that the shooter appeared to have acted alone.

They also pushed back on any criticism of the police response to the shooting — for hours, authorities were one step behind the assailant — and offered more details on the events that led up to it.

The police received information early on Thursday afternoon that a man who might be armed had threatened to kill himself and was on his way to Prague, the authorities told the news conference. A nationwide search for the man was initiated and by 1:15 p.m. had narrowed to focus on Charles University, they said.

The first shots rang out just before 3 p.m., and police were on the scene in four minutes, according to authorities. The police began to search for the gunman and within 30 minutes had him surrounded on the roof, authorities said, adding that hundreds of officers were involved with the operation.

“People may criticize the police and say it should have happened sooner. We need to understand that the perpetrator was hiding,” said Petr Matejcek, the director of the Prague regional police department. “There are a number of buildings around, there were people who were watching, and it would have been very unfortunate if the use of firearms by police caused further injuries.”

Authorities identified the shooter only as David K. and said that they believe he fatally shot his father in a town outside Prague on Thursday before heading to the university. He is also a potential suspect in the double murder of a baby and its father last week in Klanovice Forest, west of Prague, according to police.

Police also said that they were investigating whether the shooter was linked to a series of expletive-laden messages vowing mass murder that were posted in Russian on the Telegram messaging platform under the name David Kozak.

“I hate the world and want to leave as much pain as possible,” read a message posted three days before Thursday’s massacre. “I want to do a school shooting and possibly suicide.”

The messages, viewed by The New York Times, were all written in Russian, apparently by a native speaker well versed in vulgar slang. If the shooter and the Telegram writer were the same person, it was not clear how a Czech citizen raised in a small village in Central Bohemia would have acquired such mastery of the language.

Amid a flurry of reports on social media that the gunman’s family was of Russian origin, the interior minister, Vit Rakusan, said on Friday that David K. was Czech and had grown up in a Czech family.

Authorities also were working to establish how many weapons the shooter had used in the assault. On Friday, they said that he had registered licences for eight weapons.

The Czech Republic, unlike many European countries, has a relatively tolerant approach to gun ownership. Licensing rules are strict, but the right to protect oneself and others using arms has been guaranteed since 1991 by the country’s Charter of Fundamental Rights and Freedoms.

Worried that the European Union might at some point pressure the Czech Republic to fall more in line with other countries, hunters and other gun enthusiasts have successfully lobbied Parliament to enshrine that right in the Constitution — the closest European equivalent to the Second Amendment in the United States.

Although there were a few calls on social media for the tightening of gun laws in response to Thursday’s rampage, they were quickly rejected as an attempt to introduce politics into the nation’s grief and denounced as disrespectful to the dead.

That reaction stood in sharp contrast to the outcry in Serbia, where back-to-back mass shootings in May killed 17 people and wounded more than 20. Serbia also has stringent gun ownership rules, but in the aftermath of the massacres, it has been convulsed by public debate about whether gun ownership should be restricted further.

But in the Czech Republic on Friday, the focus was on grief — which broke through the widespread indifference to religion in a country that ranks as one of the world’s most atheist nations.

As the first details began to emerge about the lives lost — police said that Lenka Hlavkova, the head of the university’s music studies department, was among those killed — students, faculty members and members of the public were invited to a memorial service on Friday evening at Holy Saviour Church to be presided over by a Roman Catholic priest affiliated with the Faculty of Arts.

Albert Marsik, a graduate student at Charles University, was struggling on Friday to make sense of what had taken place a day earlier. He said he was delivering a presentation in a linguistics class Thursday when he heard shouting.

“Nobody shouts here ever,” he said of the building, where students study subjects including English literature, sign language and philology. “It was suspicious immediately.”

Then he heard sirens and gunshots, Marsik said in an interview, before police arrived at his classroom and ordered everyone to evacuate. They rushed out, unscathed, as the gunshots continued.

The university had been one of the safest and most idyllic places he had ever known, said Marsik, 25. The shooting changed that.

“I’m sure we are capable of putting all the effort we can into keeping this safe space,” he said. “But it definitely damages this feeling that everybody has had forever.”

-New York Times