The 17-year-old victim was found severely injured after the attack at the Friskis & Svettis training centre at around 6pm on Saturday. Police immediately apprehended the 15-year-old suspect and he was formally arrested a few hours later.
The Friskis & Svettis in Ängelholm wrote on its website that the attack involved a knife and that fellow gym-goers intervened in the assault and helped to save the victim's life. The gym said it would increase its security as a result of the incident.
“Our thoughts go out to the victim and his relatives. We also feel great gratitude to all the members who helped save lives and deal with the situation at Batterifabriken [a section of the training facility],” company CEO Bodil Nordkvist said.
The victim was left in a serious condition as a result of the attack.
Police plan to carry out a full-scale forensic investigation at the scene of the crime on Monday.