Domino

At the scene of a terrible murder, only Toudou is able to find the surviving little girl in the closet—his niece Tsubasa. Four years later, Toudou and his father are caring for Tsubasa, who no longer speaks, and Toudou continues to work as a police detective. He's assigned to a new partner, a young woman with a promising future, Saeki. As Toudou and Saeki team up to solve murder cases together, they will also both have to confront their own painful pasts.

(Source: MangaHelpers)