Eriko Mukai

 (向井 絵里子, Mukai Eriko ) is a subordinate to Kageyuki Shiraishi. She works for the Field Operations Support Team section the Shinjuku Police Department. She hates Shiraishi and doesn't try to hide it, going as far as forming a Shiraishi hate group along with Sakuragawa, whom she has a good relationship with, and later invites Hoshino to join.