BERLIN: German police acting on an FBI tipoff arrested an alleged online sadist accused of driving a 14-year-old US girl to hang herself, prosecutors said on Friday.

The suspect was linked to an online group called `Nefarious Maniac Kult`, or `NMK`, part of a global network known by the labels `764` or `COM`, the Hamburg public prosecutor`s office said.

The case echoes others in a dark online subculture where predators manipulate, exploit and extort young victims -a category of crime that has been labelled `nihilistic violent extremism`. The 18-year-old German was arrested in Hamburg on Thursday, accused of being the indirect perpetrator of murder and grievous bodily harm.

Between September and October, the suspect allegedly `exerted influence` via the social network Discord over the girl from Indiana state, whom prosecutors described as `psychologically fragile`.

The suspect allegedly pressured the girl to cut herself and write the letters `NMK` on a wall in her own blood, and had her send him video recordings of these acts. A few days later, she hanged herself in her bedroom, prosecutors said.-AFP