Three teenagers arrested on suspicion of copying ISIS execution videos

The brutalised and naked body of Ryota Uemura was found in undergrowth near a river last Friday. His neck had been repeatedly hacked at, apparently with a knife, discovered nearby soaked in blood.

Low-crime Japan has been captivated by the killing, with media reporting every twist and turn in the investigation, including details of how the youngster's mobile phone was used to send a friend request on a messaging app around the time of his death.

Populist weekly Shukan Shincho reported the wounds appeared to indicate that whoever killed Ryota may have been trying to decapitate him.

'Some investigators suspect (the criminals) watched Internet videos showing the execution of hostages by Islamic State (IS) fighters and sought to mimic them,' the magazine said, quoting an unnamed source close to police.

Japan is still reeling from the brutal murder of two of its citizens - war correspondent Kenji Goto and his friend Haruna Yukawa - by Isis fanatics in Syria.

Kanagawa Police Department on Friday arrested an 18-year-old boy and two 17-year-olds, whose names were withheld because they are legally minors, on suspicion of murder, public broadcaster NHK and other media reported.

While a police spokesman declined to confirm the reports, investigators also obtained arrest warrants for two other teenagers over the murder in Kawasaki, an industrial city southwest of Tokyo, media said.

Junior high school student Ryota reportedly knew the suspects, and had been attacked by them previously, media said.

Violent crime is exceedingly rare in Japan and becomes very big news when it occurs.

(dailymail.co.uk)