CHILLING footage captured the moment a heroic man cried out for the Prague gunman to "shoot here" in a bid to distract the killer from his rampage.
David Kozak, 24, killed 14 and injured 25, in a horrific massacre at a university in the Czech capital yesterday - a week after allegedly murdering a dad and a newborn baby.
The terrifying video from the scene of the attack shows Kozak - a history student who fantasised about "becoming a maniac" - prowling around a rooftop at Charles University.
Armed with an automatic rifle and dressed in black, the shooter is filmed calmly picking off his victims one by one.
A brave man can then be heard screaming: "Hey you, shoot here f*****!" in a bid to halt Kozak's bullet barrage and save the lives of others.
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Undeterred, the crazed gunman continued with his killing spree as he turned to aim at people on the ground and loud shots rung out.
"He is shooting, get to cover," the man shouted.
He then desperately tried to alert police to the 24-year-old's exact location to put an end to the bloodshed.
The massacre began on Thursday afternoon at around 3pm when Kozak opened fire at the Faculty of Arts building in Jan Palach Square - an area popular with tourists and Christmas shoppers.
And under a hour later, Kozak had committed the worst mass shooting in the Czech Republic's history - leaving 14 dead and 25 injured, including 10 seriously.
Cops soon after found Kozak's body after he allegedly turned the gun on himself.
Police have released terrifying bodycam footage them storming the university building to hunt the active shooter down.
The masters student has been described by neighbours as a "nerd" who was fascinated with guns, while cops say he had his own "huge arsenal of weapons and ammunition".
Prior to the horror shooting spree from the rooftop of his university, Kozak killed his own father in the village of Hostoun - 13 miles outside Prague.
Police also believe he killed a 32-year-old dad and his two-month-old baby in a "random" forest attack close to Prague in Klanovice on December 15.
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Hundreds of cops combed the area after shooting as investigators probing whether the two killing sprees are linked.
Vondrasek told reporters: "We are working very seriously with the fact that the attacker... is also responsible for the two victims from the end of last week."
Cops discovered the body of Kozak's dad at 12.45pm and then found the killer's threats on Telegram.
Armed officers raced to Kozak's university building where he was due to attend a lecture at 2pm.
Police evacuated the building by 2.22pm, according to local media.
But at 2.59pm, reports emerged of shots being fired as Kozak began his murderous rampage.
Kozak's online posts appear to reveal his chilling plans to "do a school shooting and possibly suicide" - inspired by a Russian school shooting on December 7.
Alina Afanaskina, 14, shot a student and wounded five others before turning the gun on herself in Bryansk.
“Alina Afanaskina helped me too much," Kozak, a Russian speaker, said in his Telegram messages.
"I always wanted to kill, I thought I would become a maniac in the future.
"I realised that it was much more profitable to do mass murders rather than serial ones. I sat. Waited. Dreamed.
"But Alina became the last point. It was as if she had come to my aid from heaven just in time."
Police Chief Martin Vondrasek confirmed Kozak - a legal gun owner - went to Prague with a rifle in hand after being "inspired by a horrific event, a similar event, abroad".
And according to Dutch newspaper Volkskrant, Kozak may have been helped by his girlfriend - who is now said to be trying to flee abroad.
Footage from the attack showed terrified staff and students barricaded themselves inside their classrooms with piles of chairs and tables.
Others were seen leaping from windows onto ledges as they tried to escape.
One of the victims has been identified as Lenka Hlávková, the director of the Institute of Music Science at Charles University.
The department said in a post on Facebook: "We express our deepest condolences to all the bereaved, especially to the family.
"It's extremely cruel news for all of us. Let's stay supporting each other."
The Czech government has declared a national day of mourning for the victims on December 23.
Dan, a British policeman, was in the city for an annual Christmas market trip with his Slovakian wife and 25-year-old daughter.
He told The Sun: “We ran with our hands up as soon as the ‘crack, crack, crack’ of gunfire rang out.
“It was such an alien sound because we had been listening to carol singers and browsing stalls as the bullets started flying. We did not know if we were running towards the gunman, or away from danger.
“Three people were slain. They lay in pools of blood, where they had stood enjoying the festive scene.
“A guy to the right of me was shot across the chest. We were just lucky.
“It was like something out of a movie. It was total panic.”
Another Brit dad told of the horrors his family saw when the gunman opened fire and they were forced to flee.
Despite still being visibly shaken up and shocked he spoke to The Sun, saying: "My daughter said, 'Dad, look up there, there's a guy on the roof'.
"And all of a sudden it just went mental, it sounded like a load of firecrackers.
"I would have said about 30 people got shot. There was a guy lying dead on the right hand side of the square. He was shot in the chest."
Joe Hyland, 18, of Truro, Cornwall, was on holiday with friends when he heard the gunshots.
He said: “We ran for cover in the metro after police shouted at everyone to run. It was very frightening.
“All of a sudden people started running. We didn’t know what was going on. We saw police going past us. They were shouting, ‘Run!’”
Prague's mayor Bohuslav Svoboda said he was "completely shocked" by the gun horror.
And Czech Republic's Prime Minister Petr Fiala said the "brutal attack affected our entire society".
"We are going through a painful and sad time, our thoughts are with those who were directly affected," he said.
"We have to deal with this situation together. Please, let's stick together in these difficult times."
Gun crime is relatively rare in the Czech Republic.
However in December 2019, a 42-year-old gunman killed six people at a hospital waiting room in the eastern Czech city of Ostrava before fleeing and fatally shooting himself, police said.
