Unbanded

James Holden, a former revered homicide detective turned professor, has suffered through a lot of traumatic experiences including the death of his wife. In a recent string of disturbing murders, all linked by a wedding ring, Holden is asked to help solve the case by a young detective, who has idolized him for years. Kim, his new mysterious and attractive research assistant, complicates the case and Holden's personal life as the race to find the killer progresses. He soon realizes that the killer may be closer than anyone could have thought. - IMDb