School massacre probe police doubt internet postings

The psychological profile of a teenager who went on a shooting spree at his former school and killed 15 people began to take shape, as German investigators described a withdrawn young man from an intact family who broke off psychiatric treatment for depression.

But investigators faced a setback as they struggled to authenticate a chat room posting that purportedly warned of a bloody rampage hours before 17-year-old Tim Kretschmer wreaked havoc on the quiet town of Winnenden near Stuttgart, southwest Germany.