The boy, who went by aliases such as "Mr Killer" and "The Godfather", has been convicted of participating in two attempted murders and a bombing in Copenhagen.
He was 15 years old when he participated in the planning. No one was injured in the events.
A unanimous court finds that this is a "carefully planned crime carried out with several other people."
The court also emphasizes that the attempted murders were intended to create conflict between two criminal gangs.
According to the Ritzau news agency, the 16-year-old, who wishes to be acquitted, has already appealed the verdict.
