In a decision on Monday, Eastern Uusimaa District Court formally banned criminal gang the United Brotherhood (UB) as well as its affiliate Bad Union.
The ban was called for by the Police Board and the local prosecutor.
It was reported in January 2020 that the groups claimed they were shutting down operations after becoming the target of a temporary ban.
In Monday's ruling to permanently ban the gangs on authority of the Association Act, the court noted that the organisations were set up to carry out serious crimes, were hierarchically organised, used gang colours and had also been armed.
Special prosecutor Anna-Riikka Ruuth said she was pleased with the court's decision.
"In our opinion, there was clear evidence, for example, regarding the illegality of the United Brotherhood. They have committed tremendously serious crimes," Ruuth said.
The district court's decision, however, was not final as the ruling can still be appealed.
In practice, the banning means that the outfits are forbidden to utilise gang colours, to maintain club premises or to recruit new members.
The Police Board is soon expected to issue updated guidelines to law enforcement personnel about how to intervene with criminal organisations.
Still operational outside Helsinki, Turku
According to police, the United Brotherhood's activities have not been visible recently outside of prisons. In Helsinki and Turku, for example, membership in the gang is almost exclusively conducted within the walls of penal institutions.
However, according to the National Bureau of Investigation (NBI), the organisation has continued to operate and, among other things, still use the United Brotherhood's red and black colours in the city of Joensuu.
In its decision, the court noted the group had continued to operate in the municipalities of Jyväskylä and Ylöjärvi and in the city of Tampere.
"Many of the gang's members are in prisons and they have a kind of dominance over other inmates," said detective chief inspector Kari Siivo from the Police Board.
The United Brotherhood was established in 2010, following a merger of the criminal gangs Natural Born Killers, M.O.R.E. (roughly translated as "we are the criminal elite") and Rogues Gallery.
Authorities have characterised the United Brotherhood as Finland's most dangerous criminal organisation.
Currently the majority of the gang's members are serving prison sentences for serious drug, violence and firearms offenses.
Monday's court-ordered banning was the first such action taken in Finland. In a similar move in 2019, the Netherlands banned the activities of the criminal Hell’s Angels motorcycle club.