The accused Mohammed Mustafa had yesterday followed the 18-year-old German student, who had come to visit an ashram at nearby Panir as part of her research, they said.
He waylaid her while he was walking along the road and molested her.
Hearing her screams, the locals gathered and beat him up black and blue before handing him over to the police, the sources said.
Family members of the youth told the police that Mustafa was mentally unstable and had been receiving treatment at the Wenlock hospital here.
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