The National Police Agency said Thursday that it will establish a new office aimed at collecting and analyzing information on masterminds in tokuryū — loosely organized crime groups made up of anonymous members.

Also, investigators will be gathered from around the country to arrest the leaders of tokuryū groups, which use members connected through social media to engage in various illegal activities such as fraud, robbery and drug trafficking.

Tokyo's Metropolitan Police Department, which is central to the country's investigations into tokuryū groups, will carry out a major reorganization to accommodate such investigators.