Stephan Balliet, 27, was captured by police on Wednesday after he shot dead two people in a gun rampage in the city of Halle.
Halle gunman was frustrated, computer-obsessed loner
The German suspect in a deadly anti-Semitic attack targeting a synagogue and a kebab shop in the east of the country was a frustrated, computer-obsessed loner who lived with his mother.
The suspect in the deadly anti-Semitic attack once served in the German army
"The boy was only ever online," spending many hours at the monitor and with few friends, his father, who was not named, was quoted as saying by Bild newspaper.
He had lived with his mother since his parents divorced when he was aged 14, the paper said.
While Balliet finished school, he had to break off chemistry studies at university after a serious stomach operation, it reported.
ADVERTISEMENT
He also served in the Bundeswehr (German army), and several people who saw him during the attack said he looked "professional" or trained in weapons use.
Federal prosecutors have taken on the investigation after the attack was labelled an especially serious crime.
They told the DPA news agency on Thursday they had secured evidence in a search of the shooter's home in the small village of Benndorf, some 40 kilometres (25 miles) west of Halle, or around 200 kilometres southwest of Berlin.
A neighbour told Bild that Balliet worked as a broadcast technician.
His father, who still regularly saw his son, told Bild: "We fought very often, my opinion counted for nothing. I can't reach him any more."
ADVERTISEMENT
Balliet "wasn't at peace with himself or the world, he always blamed others", he added.
'Total loser'
Throughout a video the shooter made of his actions using a helmet-mounted smartphone, his rage bubbles to the surface.
In the earliest minutes he berates his laptop as it takes too long to load programmes and find a wireless signal, while later he curses as his homemade weapons fail to fire.
Unable to breach the entrance of the Jewish cemetery outside the synagogue, he shoots a passing woman, later firing another burst into her lifeless body and shouting "Pig!".
ADVERTISEMENT
But he reserves his harshest language for himself, calling himself a "fucking idiot", a "failure" and a "loser".
Bleeding after a gunfight with police as he flees town in his crippled vehicle, he apologises to the imagined audience watching online.
"That was it guys. A total loser," he says into the lens before hurling the phone out of the car.
Around 2,200 people are believed to have watched his blundering, violent rampage on games streaming platform Twitch, the Amazon-owned company said -- only five of them live.
'Global radical right'
ADVERTISEMENT
Balliet's repeated addresses to watching "guys" -- and invitation to "be my friend" at the end of a political diatribe against Jews at the start of the video -- point to a self-identification with a wider movement, extremism researcher Matthias Quent told DPA.
The use of English and transmission of conspiracy theories targeted at Jews and feminism "are themes of the global radical and populist right", Quent said.
It was "significant" that he had written and published a "manifesto" in English, tweeted Peter Neumann, a terrorism expert at King's College London.
The choice "clearly shows that he wasn't trying to impress local neo-Nazis, but that his 'audience' was on message forums" online that have previously cheered on far-right killers.
JOIN OUR PULSE COMMUNITY!
ADVERTISEMENT
Eyewitness? Submit your stories now via social or:
Email: news@pulselive.co.ke