Criminal Investigation Bureau, division 3: Controlled substances or organized crime. He's not pleased about dealing with folks like the Yakuza, but somebody's got to do it. Volunteers for low-risk operations whenever he can, but he's there for the big busts that need everyone.
Criminal Investigation Bureau, division 3. Rie the supercop isn't gonna be stopped by NOBODY, you got that? Kurogane-kai, in her neighborhood? I don't think so! Rie is a loose cannon that plays by her own rules, which is why she's partnered with Yamato, who plays by the department's rules.
Criminal Investigation Bureau, division 1: Homicide or unregistered weapons. Nishiyama is doesn't have a lot of murders or weapons for Yumi to deal with, so she often gets tapped by her sister Rie to cover her paperwork. She has trouble saying no.
Criminal Investigation Bureau, Forensic Section. Noriko is kinda stumped easily, and her idea of Nishiyama as an idyllic neighborhood gives her a bit of a bias to claim incidents as accidents or suicides. Sometimes she stumbles across things that seem a bit... supernatural. But she'd get thrown out of the department if she started saying stuff like that, right?
Criminal Investigation Bureau, safety department. Tetsuo is a sweet old man who gives teenagers a lot of slack, but is pretty responsible and gets the job done. Rumor has it that he used to be a master detective back in the day... well, it's not really a RUMOR, it's totally on file, but people treat it like a rumor because it's pretty hard to believe.
The dogmatic leader of the Security Bureau, enforcing violations of the Alien Registration Law/Foreign Residents Registration System. Lucy runs a tight ship, and nothing gets past her indefinitely. A true paperwork guru whose focus is legendary.