"Harvey killed the guy at the bar. Harvey shot Maroni's driver and the car flipped, so it's assumed that Maroni + driver died as a result of the accident.
Dent doesn't kill Ramirez, but I'm assuming that he killed the other two cops (perhaps the same cops that dropped off the envelope to the judge) that were sent to pick up Gordon's wife and kids. Keep in mind that Ramirez said she had called off the two cops that were supposed to pick them up, and this is assuming that they had actually showed up to Gordon's residence with Ramirez in the first place."
As Maroni is getting into his car, Dent snatches a guy. This is very quick and subtle, but you can assume he killed that guy before he got in the car to talk to Maroni.
So, there is the guy at the bar, the guy outside of the car, the driver of the car.
Also, does it ever show the driver? One guy lets Maroni into the car, but I'm not sure if that is the driver or maybe even somebody else that rides in the front seat. It is tough to tell since the guy lets Maroni in the car and the next camera angle shows them in the car moving. So the guy that let Maroni in is either the driver (and he got to the driver seat extremely fast despite letting Maroni in at the back right door of the car), or he is in the passenger seat, or he never got in the car at all. But if he did get in the passenger seat, that leaves us with another option for the body count.
He killed:
1. The bartender
2. Sal Maroni
3. Sal Maroni's bodyguard
4. Sal Maroni's driver
5. The black woman working for the police department (I forgot her name).
I remember Gordon saying "5 people killed, 2 of them were cops". We already know the 2 cops Harvey killed were the bartender and that black woman. And out of the 3 people that Harvey killed, only two of those kills were shown on screen and one was off-screen. The kills on screen were the killing of Sal Maroni and his driver. The kill shown off-screen was the killing of Sal Maroni's bodyguard. Do you remember when Sal Maroni got into his car and expected to see his bodyguard in the car instead of Harvey?