"A normal boy" - that is how his table-tennis coach has described Tim Kretschmer, the 17-year-old who has been named locally as the suspect in Wednesday's deadly school shooting in south west Germany.
Eckehard Weiss coached Kretschmer for three-and-a-half years.
"He was a normal kid. Not aggressive. Sometimes he could be quite arrogant, but then he was one of the better players, so that's understandable," Mr Weiss told the BBC News website.
Mr Weiss, who trained Kretschmer on a regular basis until he switched to another table-tennis club 18 months ago, says that apart from his talent for table tennis, the boy was unremarkable.
"He dressed like a normal boy, and the way he dealt with his team-mates was normal, too."
The coach lost contact with Kretschmer when he switched to a nearby club. "But I know he played a league game just this past Sunday," Mr Weiss says.
Mr Weiss says that in the years he coached the boy, he came to know him well.
"He was a keen player. When he was 11, he told me he would one day want to become a professional player."
Mr Weiss says playing table tennis was Kretschmer's only hobby and that he took it very seriously.
"Whenever a new ranking was published, he'd learn the names of the top 40 players by heart."
The coach says there was nothing unusual about Kretschmer's home life that he knew of. He says the family were very welcoming.
"His three team-mates and I would often go round to his house after league games for coffee and cake and play table tennis in the cellar."
"Tim never mentioned having any arguments at home. They seemed like a happy family," Mr Weiss says.
"He also got on fine with his three team-mates," says Mr Weiss. "They weren't close friends, but there was no friction there either."
Mr Weiss recalls that winning the area championship in 2004 in the boys' under-14 category was a happy moment for Kretschmer.
Looking at the picture of Kretschmer holding the trophy aloft five years ago Mr Weiss says: "Yes that is him, that's Tim, the table-tennis player, there was nothing aggressive about him then."