Tim Kretschmer's coach says he seemed to have a happy family life
The teenage gunman who issued a chilling internet warning just hours before going on a deadly shooting rampage in his former school in south-western Germany was known by most of his neighbours and friends as "a normal, unremarkable boy".
Tim Kretschmer, 17, wearing black combat fatigues, on Wednesday shot dead nine students and three teachers in Winnenden and then three passers-by in the neighbouring town of Wendlingen before turning the gun on himself.
In his chatroom warning the night before the shootings, Kretschmer wrote: "I've had enough. I'm fed up with this horrid life... Always the same. People are laughing at me... No-one sees my potential... I am scared, I have weapons here, and I will go to my former school tomorrow and then I will really do a grilling."
Kretschmer had a passion for guns and liked violent computer games, people who knew him admit, but he never did anything to arouse suspicion in his home town of Leutenbach.
And hardly anyone could have suspected that Kretshcmer - who last year received psychiatric care - may be suffering emotionally or even having some sort of a split personality.
"He was a normal kid. Not aggressive," Eckehard Weiss, who had been Krestchmer's table-tennis coach for several years, told the BBC News website.
"Sometimes he could be quite arrogant, but then he was one of the better players, so that's understandable. He dressed like a normal boy, and the way he dealt with his team-mates was normal, too," said the coach.
"He was quiet but he had friends. He was funny," Marcel Rupp, one of Kretschmer's friends, was quoted as saying by the Times newspaper.
"He told me he was interested in guns, but I thought in a normal way," Marcel said.
Tim Kretschmer lived with his parents and a younger sister in Leutenbach, about 12km (7.5 miles) from Winnenden.
The family was well integrated into the local community, and there was nothing unusual about Kretschmer's home life, local residents say.
"Tim never mentioned having any arguments at home. They seemed like a happy family," Mr Weiss said.
"They were very friendly. They had a lot of money and a big Mercedes," Jutta Lautenschlager, who works at a post office in Leutenbach, was quoted as saying by the Times.
Kretschmer's father - a respected businessman and a member of a local gun club - had a small arsenal of licensed guns which he kept in a locked cabinet.
It now appears that on Wednesday Tim Kretschmer used one of the guns - reportedly a Beretta - that was left in his father's bedroom, along with hundreds of rounds of ammunition.
Investigators are still baffled about his motivation for the shootings.
There has been speculation that Kretschmer - described by some of his former classmates as "a loner" who never had a girlfriend - could have held a grudge against his school.
Some media reports suggested that he deliberately targeted girls - 11 of the 12 victims at the school were female.
Meanwhile, police revealed that they had seized Kretschmer's computer, where they found "games that are typical for someone carrying out a mass shooting".
There have also been rumours that the gunman could have been influenced by a shooting in the US state of Alabama just several hours earlier in which 11 people were killed.
Investigators are now trying to find out why Kretschmer confessed being "fed up with his horrid life" and what triggered the shootings.
Was he trying to prove something to his peers? Was he influenced by the violent computer games? Did he hold a grudge against someone at his former school?
Try as they may, the investigators may never know what happened to a talented table-tennis player who proudly held his trophies in school pictures.