tv series, need help to find the title, pretty please!!!

Its been so many years (about 6) since ive seen first or one of the first episodes on the TV, i missed the title at that time but it was really good.
Plot goes something like this
some guy wakes up and girl he was with is dead, she got stabbed with a knife, he panics, takes the knife, walks out of the apartment but breaks the glass in the door and goes back inside (maybe then takes the knife?) then runs outside and cops routinely stop him, take him to the police dept for a checkup all is good and they let him go but just while he was walking out something happens and they check his jacket and they find this knife a murder weapon, then fuck knows whats next id really want to find out

please help me :/