A 'bullied' drop-out who turned his former school into a bloodbath on Tuesday as he massacred 10 students in a gun rampage had sent his mother a farewell video just moments before he opened fire. 

Investigators found the message yesterday when they searched the home of the 21-year-old shooter who took his life after his attack at BORG Dreierschützengasse high school in the city of Graz. 

Cops did not elaborate on investigators' findings in a brief post on social network X.

But a senior official who acknowledged that the message had been found on Tuesday night said it hadn't allowed them to draw conclusions.

Franz Ruf, the public security director at Austria's Interior Ministry told ORF public television that a 'farewell letter' had also been found.  

'He says goodbye to his parents. But no motive can be inferred from the farewell letter, and that is a matter for further investigations.'

Alarmed by his confusing message, his mother immediately notified police, Austrian news outlet Heute reports. 

But despite her efforts to stop a tragedy from happening, it was too late, as she opened the video message 24 minutes after receiving it, and by then her son had already stormed into two classrooms.

Asked whether the assailant had attacked victims randomly or targeted them specifically, Ruf said that is also under investigation and he didn't want to speculate.

He said that wounded people were found on various levels of the school and, in one case, in front of the building.

A 15-year-old Kosovan girl named Lea is the first of his victim's to be pictured. 

Mourning the teen in a Facebook post, her heartbroken aunt wrote: 'Today, my niece Lea tragically lost her life in the attack in Graz. We pray for her soul and express our gratitude to all those who share our pain during these difficult times.'

More than a dozen others were wounded as shots and screams rang out when the shooter - named locally as 'Artur A' - stormed into his old classroom blasting a shotgun and a pistol which he legally owned.

In the country's worst mass school shooting, terror-stricken pupils pretended to be dead as they cowered in corridors and two classrooms or ran for their lives.

Chilling video captured the sound of shots followed by screams as the gunman picked off his victims.

Pupils and teachers were said to be among the dead. 

Six female and three male victims died quickly, with one adult said to be among them. The tenth victim, a woman, succumbed to her injuries in hospital last night.

The former pupil ended his deadly rampage when he turned a gun on himself in a toilet cubicle.

Police later found a suicide note at his home nearby, which said he had 'felt bullied' at the school and was looking for someone to blame, according to Austria's Krone Zeitung newspaper, although authorities said only that he was an ex-pupil who had quit before completing his studies.

The gunman is understood to have lived with his single mother in a low-income housing estate on the outskirts of Graz, Krone Zeitung reports. 

One neighbour described him as 'inconspicuous', telling Profil news outlet: 'He was completely withdrawn. He wore his large headphones and a backpack whenever he went in and out. He never said hello, but he was never unpleasant in any way'. 

His mother has been described as a 'kind' and 'truly sweet' woman, with one neighbour commenting: 'I'm praying not only for the victims' families, but also for the mother.'  

Detectives are scouring data on his mobile phone and computers to build a picture of his recent movements and search for clues as to his motivation.

Austria was plunged into a state of shock, with Chancellor Christian Stocker flying to Graz and declaring a 'dark day in the history of our country' as he announced three days of national mourning.

More than 300 police and special forces descended on the school after 'screams and gunshots' were heard by emergency service workers during frantic calls at 10am local time. 

Armed Cobra police commandos charged into the four-storey building as part of an emergency response that included 65 ambulances, at least two air ambulances and 158 paramedics.

Terrified pupils filmed themselves as gunshots rang out, and later as they fled down corridors as armed officers helped evacuate them from the 400-pupil school.

Two schoolgirls were shown clinging on to each other as they ran from the school building. One teacher described being barricaded inside a classroom with pupils as they heard the gunshots.

A distressing video showed victims lined up on stretchers outside of the school while dozens of paramedics tended to them. Some were covered by white sheets. Helicopter ambulances airlifted the most severely injured straight to Graz Regional Hospital.

Desperate parents raced to the school as word of the massacre spread, with police reuniting them with evacuated survivors at a local hall. 

One father told how his son had survived by pretending to be dead. The man, named as Farag, told television channel Puls 24: 'Out of fear, he lay down to pretend that he was killed so that he wouldn't be targeted any more.'

He added: 'Who did this? What kind of problem did he have?'

One mother said: 'My son called me to say he was in school and that he was being shot at, and that he thinks he is going to die. I've only found out now, two hours later, that he's still alive.'

Metin Ozden, who was in his kebab restaurant near the school, said: 'I've never seen so many emergency services in my entire life.' He said parents passing his restaurant were crying as they rushed to the school.

Police commander Franz Ruff said 'at least' a dozen people had been injured in addition to those killed. 

Krone Zeitung newspaper previously reported that 28 people were taken to hospital, with at least two of them in an 'extremely critical condition'. Seven required emergency surgery. 

Some victims had reportedly been shot in the head. The numbers have not been officially verified.

Police confirmed the killer had legally owned the weapons, with the Salzburger Nachrichten newspaper reporting he had purchased one of the guns just days ago.

Attacks in public are rare in the nation of almost 9.2 million people, which ranks among the ten safest countries in the world, according to the Global Peace Index.

Last night the country's Chancellor said: 'A school... is a space of trust, of security, of the future. The fact that this safe space was shattered by such an act of violence leaves us speechless.'

Austria's foreign minister Beate Meinl-Reisinger said: 'As a mother of three children, my heart is breaking.' The local state governor Mario Kunasek said 'the green heart of Austria is crying', while president Alexander van der Bellen said: 'This horror cannot be captured in words.'

Leaders from across Europe sent their condolences including Ukraine's president Volodymyr Zelensky who said he was 'deeply saddened'. French education minister Elisabeth Borne said that one of those who died was a 'young fellow citizen' of France.

At a news conference earlier in the day, Austria's interior minister Gerhard Karner refused to be drawn on 'speculation' in the case, saying it was the job of the criminal office to investigate. 

Police did confirm the killer was not 'known' to authorities before the attack.  

Last night Graz Cathedral held a service of reflection and the city's main square became a 'sea of lights' as candles were lit for the victims. 

In a nearby parish church, prayers were said for victims including one called Leo. 'We are lighting a light for Leo,' said Father Pesendorfer, who was in tears.

Today, a nationwide minute's silence will be held at 10am local time. Flags on the Hofburg Palace in Vienna, where the president has his office, will fly at half mast.

Yesterday afternoon long queues formed outside a blood donation centre in Graz. Johanna, 30, said: 'I'm here because I wanted to do something. I felt helpless.'

Austria has one of the highest rates of gun ownership in Europe, with roughly 370,000 Austrians legally owning 1.5 million registered firearms, according to the interior ministry.

Wild hunting is popular in the country and more than half of Austria's registered firearms fall under the category of weapons that can be owned by any adult without a licence.