It was on November 7 last year that two students were stabbed outdoors at a school in central Hallsberg.
A then 19-year-old man was arrested three days later when he voluntarily came to the police station. He has admitted during the investigation that he was at the scene but denies any crime.
Prosecutor Robin Andersson says in a press release that the incident was triggered by a conflict.
"It has not been a senseless act, the parties involved have known or known of each other".