A 16-year-old boy has pleaded guilty to killing a 7-year-old girl in a case Austrian authorities say has raised fears that the victim's relatives might seek revenge, according to the dpa news agency.
The families of the defendant and the victim are originally from Russia's Chechnya region, the Germany news agency said.
The boy pleaded guilty on December 19, telling a court in Vienna that a voice in his head ordered him to stab the girl -- a neighbor -- with a knife, dpa reported.
Police were on high alert over fears that relatives of the girl might seek revenge, dpa reported. The names of those involved were not being disclosed to the public.
The girl's father has been missing since June, when he fled from a prison in Italy, where he had been convicted of smuggling migrants.
Police said the crime occurred in May of this year, when the teenager had invited the girl to eat ice cream in his apartment while his parents were away.
One psychiatrist told the jury that the crime was caused by untreated schizophrenia, while another said the boy was able to distinguish right from wrong despite a severe personality disorder.
If convicted, he faces up to 15 years in prison as well as open-ended admission to a mental facility.