I'm guessing at least 20 minutes were cut from the film we saw, based on footage from trailers that didn't make it (the shot of Batman running atop cop cars at night isn't in the movie,) some rumors here and there and the early word the film would be 3 hours long.
But, the whole 5 people dead, 2 of them cops, and at best we saw 4 people (more likely 3) murdered by Harvey, really leads me to believe there is missing footage. Nolan's a details oriented director. Based on his filmography, I doubt he'd let a detail like this just lie there in the film without showing it to us. So, perhaps there's scenes of Harvey killing 2 or more folks (one of them a cop.)
OR, I think Det. Ramirez might've killed herself and her death is being attributed to Harvey. She did appear quite remorseful over her actions and she didn't act as an informant/plant for Maroni for personal greed, she did it to take care of her sick mother.