Tim Kretschmer was treated at another clinic in nearby Weissenhoff
between April and September before his care was transferred to the
centre in Winnenden.

But he never resumed the outpatient therapy sessions, investigators said.

Police have meanwhile been looking into the authenticity of an internet warning said to have been posted by Kretschmer.

A police spokesman, Klaus Hinderer, said a search
of the 17-year-old’s computer had found no evidence that he had made
the posting.