The Seventh Agency

The Seventh Agency (七號機関) is a criminal group created by the government, responsible for hiding scandals, political crimes cover-ups, illegal tactics, and many more things that regular government workers would not normally comprise.

The Decay of Angels/Hunting Dogs Arc
The Seventh Agency is first mentioned by Mushitaro Oguri, which in his account is the organization that held responsible for his captive, exploiting his special ability to help erase evidence of their crimes.

Upon a questioning by Oguri, Ango Sakaguchi confesses about employing the organization, albeit only once to help erase Osamu Dazai's past crimes to atone for the death of his friend, Sakunosuke Oda.