A Japanese gang used two teenaged girls to lure a man through an internet dating site so they could mug him.
The 11 gang members, aged between 16 and 18, were arrested along with the girls, aged 16 and 17, on suspicion of robbery and assault following the incident.
Police also issued an arrest warrant for another man, 25, an associate member and supporter of the gang, who may have acted as a Fagin-type figure behind the robberies.
The youths left their victim in his underwear after throwing away his clothes, and smashed his mobile phone to prevent him contacting the police.
Investigators said that the gang members planned the robbery to raise 600,000 yen (£3,300) to have their clothes embroidered with distinctive gang patches.
The girls lured their victim through an internet dating site on 14 March with offers of sex. They arranged to meet him at the Tama River in Kawasaki.
But when the would-be Romeo arrived the gang beat him with a metal bat and stole 32,000 yen (£175) from him, police told the Mainichi Shimbun newspaper.
After the beating, the victim said: "I'm never going to use a dating site again."
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