I got two siblings in a Japanese police force, take your pick! Haruka's the (mostly) white-haired older sister! Mugen's the taller, younger brother with (mostly) black hair. They got a good brother-sister relationship outside of work. On the job, though?? Ehhhhhhh, not so much.
EDIT: Up to you though, I just noticed you closed the requests, not sure if you did it as I was looking for the image in my computer